You are Here: Home >< Maths

# OCR S2 - Jan 2010 watch

1. ah ill definitely loose a few marks then... hopefully only a few
2 for first part of 9 - and say 3 for the last bit of 7 with another 2 for error carried forward?
2. 7 partt 2 varience = 67 - mewsquared =67-64= 3

also iv its the probability of P(x>or equal to 2)= 1-P(x< or equal to 1)

= 1-[e^-3m multiplied by (1+3m)]
and then u plug the 1.29 and 1.3 to get 0.898 and 0.901 so 0.9 must lie between the two...
3. yeh... i did that - sorry if i didnt explain it very well... by no means those answers are right - just what i put
4. It's a good place to start, though.
5. Also the question about comment on the claim... I think it would be valid to say u do not have enough evidence to reject the claim since u rejected hnaught but that doesnt make the claim correct either... there was a similar qu. in june 06 or jan/june 07 i think
6. What was the reason that the last part of the final question was an approximation?
7. (Original post by Gallant92)
I accepted H0 for 4 time wasn't underestimated

I rejected H0 for 5, mean number of customers had increased.

q 7 I put central limit theorem
err can't remember all the figures but none that i'm sure are different except 5.

7 ii var was 3 because you have to minus mean^2 (64)

?
for question 4 time was underestimated... n i think u have to justify central limit theorem for qu7 by saying n was more than 30 and it was not normal distribution...
8. oh for the comment i wrote there wasnt really enough evidence - 1 mark and such an ambiguous question
9. Hopefully Mr. M may pop along and sort out any confusion? 0: ) I may pm him, It doesn't half seem a bit cheeky though.
10. eeek how'd everyone do q 8 iii??
i did 1/2[ P(type 2 | p = 0.4) + P(type 2 | p = 0.7)] and got something like 0.633.... i did get 0.3669 initially but then crossed it out in the last minute
nothing makes any sense ahhh.....
11. 6) last part i got 19.1 as my standard deviation...what did every1 else get?
12. (Original post by korobeiniki)
Hopefully Mr. M may pop along and sort out any confusion? 0: ) I may pm him, It doesn't half seem a bit cheeky though.
I'm pretty sure Mr M hates stats, so don't get your hopes up.
13. (Original post by PhyMath)
I'm pretty sure Mr M hates stats, so don't get your hopes up.
Oh fair enough, have to wait 'til monday and get a teacher to go through then.

(Original post by musicluva)
eeek how'd everyone do q 8 iii??
i did 1/2[ P(type 2 | p = 0.4) + P(type 2 | p = 0.7)] and got something like 0.633.... i did get 0.3669 initially but then crossed it out in the last minute
nothing makes any sense ahhh.....
I got 0.183 for this as P (Type II | p=0.7) = 0, i think, as 0.7 is what is being tested, and P(Type II | p=0.4) was found to be 0.3669 in 8ii
so 0.5(0 + 0.3669) = 0.183 (3sf)
anyone care to step in on that, I had a feeling it may be wrong when I first wrote it.

(Original post by examhunter)
6) last part i got 19.1 as my standard deviation...what did every1 else get?
Yeah I got that. Was a bit worried as my probability value for the standardised "z" value came to 0.6999 instead of 0.7
14. (Original post by PhyMath)
I'm pretty sure Mr M hates stats, so don't get your hopes up.

All true.
15. Hi

I have taught this to my further maths lot this term so i did a solution sheet for them. feel free to have a look.

Mr Ward
Attached Images

16. (Original post by ward309)
Hi

I have taught this to my further maths lot this term so i did a solution sheet for them. feel free to have a look.

Mr Ward
You've made a small error on the unbiased estimator for the variance in the first question, you seem to have used the wrong value for sigma x^2, using 1154.88 rather than 1154.58.

Thanks a lot though, really helpful, the rest of the answers tally up with everything I got, so if my written answers are substantial I might be on for a decent score.
17. (Original post by QED)
You've made a small error on the unbiased estimator for the variance in the first question, you seem to have used the wrong value for sigma x^2, using 1154.88 rather than 1154.58.

Thanks a lot though, really helpful, the rest of the answers tally up with everything I got, so if my written answers are substantial I might be on for a decent score.
Agreed, apart from the little mistake with the variance I got almost identical answers. I made a couple of ridiculous mistakes like not doing 1 minus the probability though so I threw away a couple of marks.
18. I haven't looked at these yet but I made the ridiculous mistake in the exam of writing P(X>7) = P(X>=6). Despite my meticulous checking that somehow escaped me. B******. Only 2 marks I guess.
19. (Original post by ward309)
Hi

I have taught this to my further maths lot this term so i did a solution sheet for them. feel free to have a look.

Mr Ward
Very useful - thanks
20. the formula for variance of a crv is integral of x^2f(x)dx - mu^2 which is 67-64=3

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: April 27, 2010
The home of Results and Clearing

### 3,867

people online now

### 1,567,000

students helped last year
Today on TSR

### IT'S TODAY!

A-level results chat here

### University open days

1. Bournemouth University
Fri, 17 Aug '18
2. University of Bolton
Fri, 17 Aug '18
3. Bishop Grosseteste University
Fri, 17 Aug '18
Poll
Useful resources

Can you help? Study help unanswered threadsStudy Help rules and posting guidelinesLaTex guide for writing equations on TSR

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE