Suggested Answers and Discussion for Methods Exam 2

[apan]

uhhh can you provide the solutions that they link to? facebook group is private

Oh crap sorry! It's on VCE discussion space, all uploaded as images. Any other way I could share them?

[brenden]

Solutions up on first page!

[BubbleWrapMan]

Apologies for any heart attacks caused by incorrect answers (if there are any).

[crystallise3]

for 3f) some people are suggesting that you have to do 50/100 * 49/99 * 50/98 =25/198

What are you thoughts on this

[BubbleWrapMan]

for 3f) some people are suggesting that you have to do 50/100 * 49/99 * 50/98 =25/198

What are you thoughts on this

That sounds right lol

[asdasdasd123]

for 3f) some people are suggesting that you have to do 50/100 * 49/99 * 50/98 =25/198

What are you thoughts on this

i did that too, as the sample size was 100 and therefore probabilty wasnt independent? not sure if im right, oh and 3d was to 3 decimal places. also for 4fi i got the same answer , except with a modulus ( in my CAS) , so i put the modulus in as the answer as well (in the brackets of loge), would i be penalised?

[angrypotato1]

for 3f) some people are suggesting that you have to do 50/100 * 49/99 * 50/98 =25/198

What are you thoughts on this

eh I feel like it can be interpreted either way as replacement isn't specified

[decentxion]

for 3f) some people are suggesting that you have to do 50/100 * 49/99 * 50/98 =25/198

What are you thoughts on this

I reckon it's implying no replacement. Once you've inspected a computer, you won't be inspecting the same computer again, so he most likely will put it to one side.

[BubbleWrapMan]

So because the function in 3h. isn't actually a probability density function, there are two possible "medians": 176.45 (integrating from 0 to m) and 176.43 (integrating from m to 210).

How many examiners does it take to define a probability density function?

[exit]

I reckon it's implying no replacement. Once you've inspected a computer, you won't be inspecting the same computer again, so he most likely will put it to one side.

I reckon that since we don't know the sample proportion, the sample of 100 was irrelevant? The probability was taken from the large population. It's not about replacing or not replacing. I can't see why the prob would be different that if he were to take each computer one by one from the large population.

[sam809]

what do you think will be the mark up, and did you struggle with the last question? because im freaking out atm 

[iroze007]

isnt the rule if np>5 then you can use binom.
100*1/2=50>5

[exit]

isnt the rule if np>5 then you can use binom.
100*1/2=50>5

if n>30, normal
if n<30 binom

Regardless of these rules, I'm definite that this was independent using both logic and what i've heard VCAA will adhere to in the future.
small pop=ncr etc.

I'm almost confident 3f) is 1/8

[iroze007]

Also for 4fii could I use a graph and limits.

[BubbleWrapMan]

if n>30, normal
if n<30 binom

Regardless of these rules, I'm definite that this was independent using both logic and what i've heard VCAA will adhere to in the future.
small pop=ncr etc.

I'm almost confident 3f) is 1/8

Yeah actually since we don't know the sample proportion it's as good as selecting with replacement. Gotta change that back.