i'm not sure how to word this, but imagine this as a question about 98% confidence interval. you would get z= 2.3263, and apply the formula to this question, zσ/rootn= 1, put z and σ in, you get n

Reply 806

olafgarten

7

Another great resource is here: http://www.drfrostmaths.com/page.php?page=21

The Revision PDF has everything you need to know in one document.

Reply 807

JoshC98

15

Original post by Ayman!

Is this alright?

\displaystyle \mathbb{P}\left ( \left | \bar{X}-\mu \right |< 1 \right )\geqslant 0.98

Unparseable latex formula:

\dispaystyle \bar{X}- \mu\sim \left ( 0,\frac{3^{2}}{n} \right )

\displaystyle \Rightarrow \mathbb{P}\left ( \left | Z \right |< \frac{1-0}{\frac{3}{\sqrt{n}}} \right )\geqslant 0.98

\displaystyle -\frac{1}{\frac{3}{\sqrt{n}}} \leqslant -2.3263 \ \text{or} \ \frac{1}{\frac{3}{\sqrt{n}}}\geqslant 2.3263

.

How did you go from step 3 to step 4?

Reply 808

Ayman!

15

Original post by JoshC98

How did you go from step 3 to step 4?

Percentage points - draw a normal curve if it isn't clear.

Reply 809

TeeEm

19

http://www.thestudentroom.co.uk/showpost.php?p=64200993&postcount=3

Reply 810

PhysicsMathsTut

10

Original post by Euclidean

Does anyone have an idea why 2015 isn't on physicsandmathstutor anymore?

Original post by Zacken

Anymore? I think he was just too lazy/cba to put it up? It's on the Edexcel website anyhow.

Come on, there must be another reason!

Original post by physicsmaths

its weird week before m3 ial june 15 was up then before the exam it was gone....
his website is so big i think he has to be very careful on what he can put up and stuff.

Edexcel is changing their policy and they will keep them locked for 12 months instead of 9 so I was asked to take them down. They still have them on theirs though...

Reply 811

username1162972

18

Original post by PhysicsMathsTut

Come on, there must be another reason!

Edexcel is changing their policy and they will keep them locked for 12 months instead of 9 so I was asked to take them down. They still have them on theirs though...

I thought so, weird indeed.
I don't see the point of locking them for another 3 months it won't help anyone.

Reply 812

Zacken

22

Original post by physicsmaths

I thought so, weird indeed.
I don't see the point of locking them for another 3 months it won't help anyone.

That's why Arsey's went down as well, I presume.

Reply 813

AakashG

1

how do you know when to include the parameters in null and alternative hypotheses for binomial and/or poisson?

Reply 814

Zacken

22

Original post by AakashG

how do you know when to include the parameters in null and alternative hypotheses for binomial and/or poisson?

You include them if they're assumed and you don't include them if you calculate it from the observed data.

Reply 815

xinchu

1

Original post by SeanFM

As far as I am aware there is nothing special about continuous uniform distributions so I would say that it is most likely a mistake.

Thank you! I have figured it out.

Reply 816

tazza ma razza

19

Original post by Zacken

You include them if they're assumed and you don't include them if you calculate it from the observed data.

if it tells you to prove the mean is S in part a, and then in part b is the goodness of fit test, would you still quote p or quote binomial is a suitable model in your hypothesis?

I am never sure if whether or not the mean is assumed when it asks you to prove the mean is a stated value

(edited 7 years ago)

Reply 817

Ayman!

15

How come we're noy allowed to use the sample mean in 6(a) but we have to use it in 6(b) on June 13R?

@Zacin

Reply 818

economicss

3

Please could someone help with question 2c https://869d950bf149eefd5cd2652b400160ceb38ca5c7.googledrive.com/host/0B1ZiqBksUHNYVGVDMmVJYzVnRnc/June%202014%20(IAL)%20QP%20-%20S3%20Edexcel.pdf how do we know to work out the mean of those 10 values? Thanks :smile:

Reply 819

Krollo

17

Original post by economicss

Please could someone help with question 2c https://869d950bf149eefd5cd2652b400160ceb38ca5c7.googledrive.com/host/0B1ZiqBksUHNYVGVDMmVJYzVnRnc/June%202014%20(IAL)%20QP%20-%20S3%20Edexcel.pdf how do we know to work out the mean of those 10 values? Thanks :smile:

We need to work out 2a+3, clearly, so equivalently we need to find a. However, in (b) you just found an unbiased estimator for a based on the mean of the observations. Hopefully you can see how you can use the data they give you from there.

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Edexcel S3 - Wednesday 25th May AM 2016

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