ATAR Notes: Forum

Archived Discussion => 2010 => End-of-year exams => Exam Discussion => Victoria => Further Mathematics => Topic started by: _avO on November 01, 2010, 01:56:36 pm

Title: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 01:56:36 pm
Solutions to Core, Graphs, Networks and Matrices below

Core
1D
2D
3B (Confirmed, it is B must use the bell curve rule and not Sx = range/4)
4A
5C
6C
7B
8B
9B
10A
11E
12D
13B

Graphs
1B
2C
3E
4E
5C
6D
7C
8A
9B

Networks
1A
2C
3B
4E
5C
6C
7B
8D
9B

Matrices
1C
2A
3E
4B
5D
6C
7D
8E
9B
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Albeno69 on November 01, 2010, 01:58:27 pm
how did u get d for question 1&2
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 01:59:57 pm
Total percentage between 179 and 181 is 37%, 37% of 300 is 111 (110)

Subtract Q1 by Q3 (roughly 181.5 - 178.75) = ~2.75 = 2.7
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Xavier1234 on November 01, 2010, 02:01:17 pm
how did u get d for question 1&2

yeah uhm. if 179-181 is 50% as per the boxplot, then 50% of 300 = 150. hence E.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:01:55 pm
No, it was 21%+16% = 37%  o.0
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: narr on November 01, 2010, 02:04:44 pm
First i put D then i put E
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:08:04 pm
For Q3 mean is approximately at 180 (give or take 0.5 away). I thought since both ways goes out by 7, it should be an equal Sx of 2 for 3 deviations
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:08:53 pm
Also if it were 3 Sd, then 9 away would still have at least 1 oven passed this point? Anyone?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: 10weid on November 01, 2010, 02:10:07 pm
CORE 8 IS D....
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:10:38 pm
No it's not if you look they chopped off 20 cm from the x.. LOL.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Xavier1234 on November 01, 2010, 02:12:30 pm
No it's not if you look they chopped off 20 cm from the x.. LOL.

i got 8B too. punched everything on cas and came up as that B.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: 10weid on November 01, 2010, 02:12:44 pm
my bad :p
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:14:00 pm
Haha me too Xavier, had so much spare time, but fuck that networks Q4 didn't read the question properly FML WHAT A NOOB.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Albeno69 on November 01, 2010, 02:15:04 pm
woudnt you say question 7 is C
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:16:22 pm
For core? I double checked chucked it into the calc and it came out as 0.778
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: iwannagetA on November 01, 2010, 02:16:41 pm
for question 5 CORE
the answer is D not C???  

Z= mean-x/s

(24.2-23)/4.2 = 0.28 which is closest to 0.3 >D


i chose D ?? is it right?? :-\
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:17:23 pm
its x - mean / sx

:/
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: iwannagetA on November 01, 2010, 02:18:49 pm
what???
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Xavier1234 on November 01, 2010, 02:18:57 pm
woudnt you say question 7 is C

its pretty moderate to strong relationship. i doubt for weak.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: vidang on November 01, 2010, 02:19:22 pm
all the same besides
linear q9
networks q7
3 wrong for matrices= q6, q8, q9
trusting your answers though

hopefully 35/40
LOL
so i can still get 40 not bad i guess
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:19:35 pm
Btw I couldn't fit the words "Graphs and relations" into the box on the answer sheet, I just wrote graphs (same with Networks and decision maths) is that okay?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: sam.utute on November 01, 2010, 02:19:41 pm
For core? I double checked chucked it into the calc and it came out as 0.778
I got the same.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: sam.utute on November 01, 2010, 02:20:22 pm
Looking like 39/40 at the moment. :D
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Xavier1234 on November 01, 2010, 02:20:39 pm
Btw I couldn't fit the words "Graphs and relations" into the box on the answer sheet, I just wrote graphs (same with Networks and decision maths) is that okay?

yeah i doubt theyre that anal about it
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:21:05 pm
Q7 networks I got 11 but then I saw the 1 (edge next to sink) and then it came out as 10, the cut however looks weird (inverted quadratic? Lol)

Q6 matrices was a trick question, you had to do UxT not TxU
Q9 Just write it out (should be AAAA, BDCB, CBDC, DCBD hence answer B)
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:21:34 pm
Looking like 39/40 at the moment. :D

Me too, depressing because my brother got 39/40 and we both got different questions wrong (networks Q4 and Q7)
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: kenhung123 on November 01, 2010, 02:21:56 pm
Does the sheet require you to put student number or anything?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:22:37 pm
No its printed on :) just had to check if it was the right number
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: sam.utute on November 01, 2010, 02:22:45 pm
Does the sheet require you to put student number or anything?
It was already typed in at the top.

EDIT: Beaten
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: sam.utute on November 01, 2010, 02:23:28 pm
Confirmation for the answer to Core Question 3 someone?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:24:15 pm
Also if it were 3 Sd, then 9 away would still have at least 1 oven passed this point? Anyone?

Dunno but from my explanation I think its B? wheres the genius when you need him/her
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: kenhung123 on November 01, 2010, 02:25:26 pm
i got B by range/8
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: sam.utute on November 01, 2010, 02:25:43 pm
I got the answer as B the first time I did it. I then did sd = range/4, and got 3 as the answer. Little iffy at the moment. Ended up putting C.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: sam.utute on November 01, 2010, 02:26:10 pm
i got B by range/8

My bound reference that I got of VCENotes said range/4!!!
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:26:43 pm
AHA i read the book Sx/4 is only ESTIMATED but its not always guaranteed?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: physics on November 01, 2010, 02:29:09 pm
OMG I am paranoid i didnt check if the student number belonged to me! :( but it was probs the same right?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:30:10 pm
Yea it's usually never different dw about it
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Xavier1234 on November 01, 2010, 02:30:19 pm
AHA i read the book Sx/4 is only ESTIMATED but its not always guaranteed?

now im fussed about matrices q6. why is it UT not TU again?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: superstar1 on November 01, 2010, 02:30:40 pm
nah im pretty sure, its range/4
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: sam.utute on November 01, 2010, 02:31:37 pm
nah im pretty sure, its range/4


WHICH ONE!?! I'M STRESSING HERE! It's the only one I might have got wrong!
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: kenhung123 on November 01, 2010, 02:31:51 pm
lol not sure well what i did was max-min/8=2=B
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:32:43 pm
I dunno but I sat there for 10 minutes reading over what the question asked, the matrix TU represents the time taken for each person to service P, F and S, whereas the question asked for UT which represents the time taken to fix all 3 different office equipment in the schools A, B and C which is what we wanted
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: sam.utute on November 01, 2010, 02:33:51 pm
lol not sure well what i did was max-min/8=2=B

Just checked on itute, and it seems that they got the answer as B as well. :(
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: superstar1 on November 01, 2010, 02:34:39 pm
b for which one.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: kenhung123 on November 01, 2010, 02:35:36 pm
3 core
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:38:33 pm
It may require some logical thinking, if the formula range/4 suggest the standard deviation is 3, that means 3 deviations away will still constitute of 0.15% ovens both sides and there are none in this question.. so.. o.0
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Studyinghard on November 01, 2010, 02:39:08 pm
are we sure about question 3? because I put in B but now that I think about it, its C because of range/4
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: rubiks on November 01, 2010, 02:39:37 pm
have you got a link to itute answers?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: sam.utute on November 01, 2010, 02:40:23 pm
have you got a link to itute answers?

http://www.itute.com/board/viewtopic.php?f=4&t=1872
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:40:29 pm
http://www.itute.com/board/viewtopic.php?f=4&t=1872

Here, unfinished though

EDIT: Beaten :p
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: superstar1 on November 01, 2010, 02:41:00 pm
which part of itute did u go on.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:41:50 pm
Forum (http://www.itute.com/board/index.php) -> further maths
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: rubiks on November 01, 2010, 02:44:07 pm
so should we take it that core 3 is b?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: sam.utute on November 01, 2010, 02:44:33 pm
are we sure about question 3? because I put in B but now that I think about it, its C because of range/4

I'm the opposite. I put C, but I think it is B now.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 02:44:58 pm
Hopefully someone can give us a definite reason to whichever one it is
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Studyinghard on November 01, 2010, 02:45:21 pm
After reading the explanation on itute ima have to go with B aswell however it is quite ambiguous. They might take both?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: superstar1 on November 01, 2010, 02:45:49 pm
i hope they take both because i circled c.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: rubiks on November 01, 2010, 02:47:57 pm
If it really is B then I get 37 :D
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: superstar1 on November 01, 2010, 02:50:36 pm
same. if it is B i also get 37.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: citizen on November 01, 2010, 02:53:01 pm
i got 37, had no clue for question 3 (core), i put d or e. can anyone please explain how question 11 core was e?
i got c, i ust don't know how it was e
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: stonecold on November 01, 2010, 02:53:48 pm
What is Q3 core?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Studyinghard on November 01, 2010, 03:00:56 pm
i got 37, had no clue for question 3 (core), i put d or e. can anyone please explain how question 11 core was e?
i got c, i ust don't know how it was e

You plot 1/x against y and then get the regression line as 249
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: naved_s9994 on November 01, 2010, 03:02:03 pm
It is C.

I'll explain why.

#1.    180 degrees is the 'median'.
#2.    Looking at the box plot, it is evident that it is skewed. Positively skewed.
#3.    The 68-95-99.7% rule, is a measure from the 'mean'!
#4.    We are unsure, but can guess the mean. (You could calculate, but it would take time).
#5.    Hence, as you are not sure of the Mean, because it is skewed the median does not equal
        the mean.
#6.    Therefore you use s= range/4  to obtain the standard deviation.

Viola:  Option C is the most correct option.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: superstar1 on November 01, 2010, 03:03:09 pm
thankyou u just boosted my confidenvce. so now im loookin at 38 out of 40.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Studyinghard on November 01, 2010, 03:03:13 pm
It is C.

I'll explain why.

#1.    180 degrees is the 'median'.
#2.    Looking at the box plot, it is evident that it is skewed. Positively skewed.
#3.    The 68-95-99.7% rule, is a measure from the 'mean'!
#4.    We are unsure, but can guess the mean. (You could calculate, but it would take time).
#5.    Hence, as you are not sure of the Mean, because it is skewed the median does not equal
        the mean.
#6.    Therefore you use s= range/4  to obtain the standard deviation.

Viola:  Option C is correct.

I wouldnt say its skewed but more approximately symmetric therefore answer is B
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: stonecold on November 01, 2010, 03:04:15 pm
Someone post up the question!!!
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: superstar1 on November 01, 2010, 03:05:36 pm
thanks now my confidence got stuffed.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: citizen on November 01, 2010, 03:06:28 pm
i got 37, had no clue for question 3 (core), i put d or e. can anyone please explain how question 11 core was e?
i got c, i ust don't know how it was e

You plot 1/x against y and then get the regression line as 249

oh ok...i did a 1/y trasformation. why isn't that right?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: naved_s9994 on November 01, 2010, 03:06:45 pm
It is C.

I'll explain why.

#1.    180 degrees is the 'median'.
#2.    Looking at the box plot, it is evident that it is skewed. Positively skewed.
#3.    The 68-95-99.7% rule, is a measure from the 'mean'!
#4.    We are unsure, but can guess the mean. (You could calculate, but it would take time).
#5.    Hence, as you are not sure of the Mean, because it is skewed the median does not equal
        the mean.
#6.    Therefore you use s= range/4  to obtain the standard deviation.

Viola:  Option C is correct.

I wouldnt say its skewed but more approximately symmetric therefore answer is B



Get a ruler out sir.
Then measure the distance from Q3 to Median , and Q1 to Median on the box plot.

It is evident it is slightly skewed.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: nbalakers24 on November 01, 2010, 03:07:21 pm
Add up the percentages. 64% is within one sd. 95% is within two sd and so on
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: superstar1 on November 01, 2010, 03:07:26 pm
thanks NAved ur the man.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Studyinghard on November 01, 2010, 03:08:32 pm
It is C.

I'll explain why.

#1.    180 degrees is the 'median'.
#2.    Looking at the box plot, it is evident that it is skewed. Positively skewed.
#3.    The 68-95-99.7% rule, is a measure from the 'mean'!
#4.    We are unsure, but can guess the mean. (You could calculate, but it would take time).
#5.    Hence, as you are not sure of the Mean, because it is skewed the median does not equal
        the mean.
#6.    Therefore you use s= range/4  to obtain the standard deviation.

Viola:  Option C is correct.

I wouldnt say its skewed but more approximately symmetric therefore answer is B



Get a ruler out sir.
Then measure the distance from Q3 to Median , and Q1 to Median on the box plot.

It is evident it is slightly skewed.

thats what I said? approximately symmetric = slightly skewed.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: naved_s9994 on November 01, 2010, 03:11:19 pm
thanks NAved ur the man.


Thanks, but your the Numero Uno 'superstar'


It is C.

I'll explain why.

#1.    180 degrees is the 'median'.
#2.    Looking at the box plot, it is evident that it is skewed. Positively skewed.
#3.    The 68-95-99.7% rule, is a measure from the 'mean'!
#4.    We are unsure, but can guess the mean. (You could calculate, but it would take time).
#5.    Hence, as you are not sure of the Mean, because it is skewed the median does not equal
        the mean.
#6.    Therefore you use s= range/4  to obtain the standard deviation.

Viola:  Option C is correct.

I wouldnt say its skewed but more approximately symmetric therefore answer is B



Get a ruler out sir.
Then measure the distance from Q3 to Median , and Q1 to Median on the box plot.

It is evident it is slightly skewed.

thats what I said? approximately symmetric = slightly skewed.

Yeah, my mis-interpretation. Sorry mate :)
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: superstar1 on November 01, 2010, 03:12:08 pm
???????
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: nickk on November 01, 2010, 03:12:25 pm

Core
1D
2D
3B (Someone check this please)
4A
5C
6C
7B
8B
9B
10A
11E
12D
13B


Matrices
1C
2A
3E
4B
5D
6C
7D
8E
9B
these look right and my suggested solutions to
Geometry and Trigonometry

1C
2B
3C
4D
5A
6D
7C
8C
9B

BUSINESS RELATED MATHS
1E
2D
3E
4B
5C
6A
7D
8B
9D
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: superstar1 on November 01, 2010, 03:12:37 pm
so wats the answer.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: johsephhh_ on November 01, 2010, 03:13:32 pm
Got suggested answers to other 2 modules Check it guys xD
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: superstar1 on November 01, 2010, 03:13:51 pm
far out i cant believ i got q9 in trig wrong. made the exact same mistake in a SAC. lol
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Studyinghard on November 01, 2010, 03:14:10 pm
I honestly think they will take two answers if WE are having trouble deciding and i emphasise we because its not like we go to the same school but we are all probably worlds apart.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: stephaheaddd on November 01, 2010, 03:14:18 pm
Question 8 CORE is C isnt it?
the fact that there it a break between the x and y axis will not affect the y intercept. the point is stationary and thus will not move regardless of the x-axis.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Studyinghard on November 01, 2010, 03:15:45 pm
Question 8 CORE is C isnt it?
the fact that there it a break between the x and y axis will not affect the y intercept. the point is stationary and thus will not move regardless of the x-axis.

Its not a point, if the line continues on it will eventually hit 141
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: superstar1 on November 01, 2010, 03:16:51 pm
q8 core is B
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: stonecold on November 01, 2010, 03:17:02 pm
I honestly think they will take two answers if WE are having trouble deciding and i emphasise we because its not like we go to the same school but we are all probably worlds apart.

please take a photo of this q.  i'd like to see it...
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Albeno69 on November 01, 2010, 03:20:02 pm
I honestly think they will take two answers if WE are having trouble deciding and i emphasise we because its not like we go to the same school but we are all probably worlds apart.

please take a photo of this q.  i'd like to see it...
question 1-3 in core were so deceptive in my opinion who agrees.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 03:20:08 pm
It is C.

I'll explain why.

#1.    180 degrees is the 'median'.
#2.    Looking at the box plot, it is evident that it is skewed. Positively skewed.
#3.    The 68-95-99.7% rule, is a measure from the 'mean'!
#4.    We are unsure, but can guess the mean. (You could calculate, but it would take time).
#5.    Hence, as you are not sure of the Mean, because it is skewed the median does not equal
        the mean.
#6.    Therefore you use s= range/4  to obtain the standard deviation.

Viola:  Option C is the most correct option.

Count 50% from the left hand side, and you get to (give or take 0.5) EXACTLY 180 so you can assume that that is the middle for the bell curve can you not? Even if you 'unskewed' it, it wont make much sense for Sx = 3, since 3 deviations away will completely leave the graph itself and therefore the remaining 0.15% both sides are missing? o.o
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Blakhitman on November 01, 2010, 03:20:31 pm
Question 1 and 3.

Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: vidang on November 01, 2010, 03:22:49 pm
the standard deviation better be 2 or im going to die
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: nbalakers24 on November 01, 2010, 03:25:21 pm
Add up the percentages. 64% is within one sd. 95% is within two sd and so on
that's why it must be 2.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: johsephhh_ on November 01, 2010, 03:25:40 pm
Hey guys is Q2 Module 3: Graphs and Relations C or E?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: stephaheaddd on November 01, 2010, 03:26:40 pm
Why isnt question 6 networks B? The 8 and 5 are backward flows, so they shouldnt be counted, right? therefore the total would be 18
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: rubiks on November 01, 2010, 03:26:50 pm
the standard deviation better be 2 or im going to die
Same here mate
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 03:27:26 pm
C, you are given 2 points (8,300) and (10,450), simply find the gradient by doing m(x-x1)=y-y1 and you get 75

For networks, the 8 is 0 however if you trace from the source to sink with 5 it can get there so therefore it still stands
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: stephaheaddd on November 01, 2010, 03:32:30 pm
why is question 7 networks B not C?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 03:33:05 pm
You can cut from the 1 instead of the 2 just looks weird
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: nbalakers24 on November 01, 2010, 03:33:27 pm
4+2+3+1 =10
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: stonecold on November 01, 2010, 03:47:42 pm
Answer to Core Q3 is B.

Question specifically said to use the rule mentioned.

Say 99.7% of the data is between 174-186

This needs to comprise of 6 regions, 3 each side of the mean.

(186-174)/6

=2
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 03:48:08 pm
Here's what you can rearrange it to look like and its more logical to make that 10 cut
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Studyinghard on November 01, 2010, 03:49:59 pm
Answer to Core Q3 is B.

Question specifically said to use the rule mentioned.

Say 99.7% of the data is between 174-186

This needs to comprise of 6 regions, 3 each side of the mean.

(186-174)/6

=2

legend :D
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: stonecold on November 01, 2010, 03:50:30 pm
It is C.

I'll explain why.

#1.    180 degrees is the 'median'.
#2.    Looking at the box plot, it is evident that it is skewed. Positively skewed.
#3.    The 68-95-99.7% rule, is a measure from the 'mean'!
#4.    We are unsure, but can guess the mean. (You could calculate, but it would take time).
#5.    Hence, as you are not sure of the Mean, because it is skewed the median does not equal
        the mean.
#6.    Therefore you use s= range/4  to obtain the standard deviation.

Viola:  Option C is correct.

I wouldnt say its skewed but more approximately symmetric therefore answer is B

I agree.  You needed it treat it as symmetrical...
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: johsephhh_ on November 01, 2010, 03:56:43 pm
C, you are given 2 points (8,300) and (10,450), simply find the gradient by doing m(x-x1)=y-y1 and you get 75

For networks, the 8 is 0 however if you trace from the source to sink with 5 it can get there so therefore it still stands
OK sounds correct but my theory is this :
u read the x axis from 2 am as 1 so 8 am becomes 4 and 10pm becomes 5 so its (4, 300) and (5,450) with the gradient being 150?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 03:58:29 pm
No, it asks for per HOUR, however the scale is 2 hours so therefore if you were to do that you must go up by 2's hence getting (4,300) (6,450) and still m=75
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: johsephhh_ on November 01, 2010, 03:59:54 pm
ah your right :)
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: eadvice on November 01, 2010, 05:00:35 pm
is core 8 D? for sure
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: scatteam_2 on November 01, 2010, 05:01:01 pm
isnt question 6 graphs E?
the feasible region in the upper triangle
so the point 3,4 satisfies that...
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 05:01:42 pm
After you transpose the equations, you have to switch the inequality (as it is previously -y) :)
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Studyinghard on November 01, 2010, 05:02:55 pm
is core 8 D? for sure

B
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Xavier1234 on November 01, 2010, 05:26:24 pm
is core 8 D? for sure

B on that. really absolutely 10000% sure
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: scatteam_2 on November 01, 2010, 05:31:25 pm
It is C.

I'll explain why.

#1.    180 degrees is the 'median'.
#2.    Looking at the box plot, it is evident that it is skewed. Positively skewed.
#3.    The 68-95-99.7% rule, is a measure from the 'mean'!
#4.    We are unsure, but can guess the mean. (You could calculate, but it would take time).
#5.    Hence, as you are not sure of the Mean, because it is skewed the median does not equal
        the mean.
#6.    Therefore you use s= range/4  to obtain the standard deviation.

Viola:  Option C is correct.

I wouldnt say its skewed but more approximately symmetric therefore answer is B

I agree.  You needed it treat it as symmetrical...

the question specifically asks for the use the 68-97-99 rule
if it didnt, i would agree with u
but i think its b
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: thompson on November 01, 2010, 05:32:56 pm
isn't quest 11 of the core C?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 05:37:03 pm
It would be C, if 1/x wasnt an option (as it has the most correlation and is positive)
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 01, 2010, 07:46:48 pm
Nvm its still negative gradient I think.. not sure can't remember
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: logix278 on November 01, 2010, 08:42:02 pm
Ummm Wtf 0.0 question 3 of matrices is not E it is B
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: logix278 on November 01, 2010, 08:43:53 pm
and question 6 of matrices is B because you just times them together
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: crayolé on November 01, 2010, 08:44:10 pm
Ummm Wtf 0.0 question 3 of matrices is not E it is B
Nah its E, you needed to inverse it
Q6 was a trick question, it's C - Try working it out manually (calculate the time it takes Vince Rani or Nav to complete School A's jobs and it's the only matrix with matching values)
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 02, 2010, 09:21:08 am
Ummm Wtf 0.0 question 3 of matrices is not E it is B
Q3 was a good one, it was basically testing your knowledge of how an inverse matrix would look like, which one would otherwise just chuck into the calc as A^-1C=X
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: Dawson on November 02, 2010, 12:02:36 pm
what was the change in graphs for the volume one?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 02, 2010, 12:03:54 pm
75 L/hr
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: sc92 on November 02, 2010, 12:52:39 pm
How is matrices question 9 'B'?!

Shouldn't it be 'E'?!
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 02, 2010, 12:54:33 pm
It asks which is true, and it's not possible to get exactly 3 answers that are the same. If you wrote out all 4 possible choices for the first question, (A,B,C,D) you can deduce that it is in fact B
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: unstable1 on November 02, 2010, 01:32:01 pm
wat is the answer to q4 number pattersn cos we i do the formula i get B as the answer but manually it says D
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: sam.utute on November 02, 2010, 01:34:07 pm
wat is the answer to q4 number pattersn cos we i do the formula i get B as the answer but manually it says D
Answer is B. Even if you do it manually, the answer will still be B. I just tried it then.
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: MrIraq on November 02, 2010, 02:17:33 pm
how did u get E for question 11 on core?

isnt it negativ trend?
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: nbalakers24 on November 02, 2010, 02:18:12 pm
1/x drags all the x values to the otherside causing a positive gradient
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: _avO on November 02, 2010, 02:18:56 pm
Just remember, to linearise you always want a positive gradient in the end
Title: Re: Suggested solutions for Core, Graphs, Networks and Matrices
Post by: unstable1 on November 02, 2010, 02:46:44 pm
wat is the answer to q4 number pattersn cos we i do the formula i get B as the answer but manually it says D
Answer is B. Even if you do it manually, the answer will still be B. I just tried it then.
oh yea ur right thanks for that i dont have to stress cos i wrote B in the exam