Login

Welcome, Guest. Please login or register.

October 12, 2025, 02:25:47 am

Author Topic: Normal Distributions  (Read 5862 times)  Share 

0 Members and 1 Guest are viewing this topic.

costargh

  • Guest
Normal Distributions
« on: August 06, 2008, 05:11:40 pm »
0
If you have the following data:
Mean 94.6
Std Dev. 45

Lower limit 0
Upper Limit 180

... can we find out what percentage of people would get over

a) 152
b) 154
c) 156
d) 158
e) 160
f) 162
g) 164
h) 166
i) 168
j) 170
i)172
j)174
????

Mao

  • CH41RMN
  • Honorary Moderator
  • Great Wonder of ATAR Notes
  • *******
  • Posts: 9181
  • Respect: +390
  • School: Kambrya College
  • School Grad Year: 2008
Re: Normal Distributions
« Reply #1 on: August 06, 2008, 05:59:03 pm »
0
dude, you did this last year :P


calculator work
Editor for ATARNotes Chemistry study guides.

VCE 2008 | Monash BSc (Chem., Appl. Math.) 2009-2011 | UoM BScHon (Chem.) 2012 | UoM PhD (Chem.) 2013-2015

costargh

  • Guest
Re: Normal Distributions
« Reply #2 on: August 06, 2008, 06:01:17 pm »
0
I know I did this last year. I tried to work it out but I wasnt getting the right answers.. I even did it on my CAS calculator

costargh

  • Guest
Re: Normal Distributions
« Reply #3 on: August 06, 2008, 06:04:28 pm »
0
Can you do one for me so I get the gist how to do the rest?

*Roxxii*

  • Victorian
  • Forum Leader
  • ****
  • Posts: 616
  • Respect: +2
Re: Normal Distributions
« Reply #4 on: August 06, 2008, 06:06:02 pm »
0
LOL LOL LOL COSTARGH!!! :D

This is for the accounting mid year isn't it?? ROFL
~2007~   * Further [41]

~2008~ * English [33]  * Accounting [39]  * Specialist [27]   * Methods [36]  * Further [45] :D  * Chinese S/L [26]

ENTER: 91.15

ii <3 Commerce #1

gtfo amy are you srs ? :P  I'm 18 are you BAH :P
FUCK JUST BECAUSE IM SMALL. :(
i have my boyfriend in my pants :P

costargh

  • Guest
Re: Normal Distributions
« Reply #5 on: August 06, 2008, 06:11:47 pm »
0
... nooo LOL

I know it can be worked out in methods and I think I'm doing it the right way and I probz am getting the right answer... but for over 152 I got 7.2% ... is that right?

Mao

  • CH41RMN
  • Honorary Moderator
  • Great Wonder of ATAR Notes
  • *******
  • Posts: 9181
  • Respect: +390
  • School: Kambrya College
  • School Grad Year: 2008
Re: Normal Distributions
« Reply #6 on: August 06, 2008, 06:14:31 pm »
0
TIstat.normcdf(152,,94.6,45)=0.101056....
Editor for ATARNotes Chemistry study guides.

VCE 2008 | Monash BSc (Chem., Appl. Math.) 2009-2011 | UoM BScHon (Chem.) 2012 | UoM PhD (Chem.) 2013-2015

*Roxxii*

  • Victorian
  • Forum Leader
  • ****
  • Posts: 616
  • Respect: +2
Re: Normal Distributions
« Reply #7 on: August 06, 2008, 06:15:21 pm »
0
... nooo LOL

I know it can be worked out in methods and I think I'm doing it the right way and I probz am getting the right answer... but for over 152 I got 7.2% ... is that right?

LOL very funny :P hahahaa

Anyways...hmm... if you are doing it correctly...then shouldn't over 152 be 10%...
like it says on the distribution table... O_o
« Last Edit: August 06, 2008, 06:18:37 pm by *Roxxii* »
~2007~   * Further [41]

~2008~ * English [33]  * Accounting [39]  * Specialist [27]   * Methods [36]  * Further [45] :D  * Chinese S/L [26]

ENTER: 91.15

ii <3 Commerce #1

gtfo amy are you srs ? :P  I'm 18 are you BAH :P
FUCK JUST BECAUSE IM SMALL. :(
i have my boyfriend in my pants :P

costargh

  • Guest
Re: Normal Distributions
« Reply #8 on: August 06, 2008, 06:19:42 pm »
0
Yeh I know... thats why I thought I was getting it wrong... anywyas what i was doing wrong was puttin upper limit at 180... why is it infinity instead of 180? Is it cause some people dont sit the exam?

*Roxxii*

  • Victorian
  • Forum Leader
  • ****
  • Posts: 616
  • Respect: +2
Re: Normal Distributions
« Reply #9 on: August 06, 2008, 06:24:39 pm »
0
ooooh can u work out the rest now and post them?
wait...can this be done on ti84 ? or only on CAS?

Omg, now i really want our SOM now...lol
« Last Edit: August 06, 2008, 06:28:13 pm by *Roxxii* »
~2007~   * Further [41]

~2008~ * English [33]  * Accounting [39]  * Specialist [27]   * Methods [36]  * Further [45] :D  * Chinese S/L [26]

ENTER: 91.15

ii <3 Commerce #1

gtfo amy are you srs ? :P  I'm 18 are you BAH :P
FUCK JUST BECAUSE IM SMALL. :(
i have my boyfriend in my pants :P

costargh

  • Guest
Re: Normal Distributions
« Reply #10 on: August 06, 2008, 06:26:48 pm »
0
Well I think something is wrong.... cause apparently 2.9% of people got 180/180 which is total bullshit....

lol and apparently 2.6% of people got 91/90 LOL

I think it might have something to do with the unassessed people? or something else. Mao? lol

Mao

  • CH41RMN
  • Honorary Moderator
  • Great Wonder of ATAR Notes
  • *******
  • Posts: 9181
  • Respect: +390
  • School: Kambrya College
  • School Grad Year: 2008
Re: Normal Distributions
« Reply #11 on: August 06, 2008, 06:29:00 pm »
0
Yeh I know... thats why I thought I was getting it wrong... anywyas what i was doing wrong was puttin upper limit at 180... why is it infinity instead of 180? Is it cause some people dont sit the exam?

its infinity because it's a normal distribution. but then, to make it realistic, it should be done with conditional probability (and not to infinity, my bad :P )



mmm, according to the stats given here, 95.3% of people get realistic scores? :P

[ps: yeah, sorry my bad. i didn't take into account there was a maximum and minimum. do it with conditional probability]
Editor for ATARNotes Chemistry study guides.

VCE 2008 | Monash BSc (Chem., Appl. Math.) 2009-2011 | UoM BScHon (Chem.) 2012 | UoM PhD (Chem.) 2013-2015

*Roxxii*

  • Victorian
  • Forum Leader
  • ****
  • Posts: 616
  • Respect: +2
Re: Normal Distributions
« Reply #12 on: August 06, 2008, 06:30:29 pm »
0
Well I think something is wrong.... cause apparently 2.9% of people got 180/180 which is total bullshit....

lol and apparently 2.6% of people got 91/90 LOL

I think it might have something to do with the unassessed people? or something else. Mao? lol

LooooL wtf ??
hmm...awww so it doesn't work properly?
i got all excited for a sec :(
Oh wells....
~2007~   * Further [41]

~2008~ * English [33]  * Accounting [39]  * Specialist [27]   * Methods [36]  * Further [45] :D  * Chinese S/L [26]

ENTER: 91.15

ii <3 Commerce #1

gtfo amy are you srs ? :P  I'm 18 are you BAH :P
FUCK JUST BECAUSE IM SMALL. :(
i have my boyfriend in my pants :P

costargh

  • Guest
Re: Normal Distributions
« Reply #13 on: August 06, 2008, 06:32:53 pm »
0
Well I dont get it. Why wouldnt 100% of people get a realistic score?

Mao

  • CH41RMN
  • Honorary Moderator
  • Great Wonder of ATAR Notes
  • *******
  • Posts: 9181
  • Respect: +390
  • School: Kambrya College
  • School Grad Year: 2008
Re: Normal Distributions
« Reply #14 on: August 06, 2008, 06:36:05 pm »
0
Well I dont get it. Why wouldnt 100% of people get a realistic score?

imperfection in the normal distribution (they can only try to *fit* people to the curve), hence it'll be approximate, but not perfect.
that and, some people didn't sit the exam (not assessed)
Editor for ATARNotes Chemistry study guides.

VCE 2008 | Monash BSc (Chem., Appl. Math.) 2009-2011 | UoM BScHon (Chem.) 2012 | UoM PhD (Chem.) 2013-2015