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OCR S2 (non-mei) watch

1. I've got the same issue! I hope to god they were looking for only sigma
2. For the doctor question, did you all reject H0? I got mean 11.76, variance 18 (unbiased estimator) and a z value of 1.92 or something like that
3. (Original post by rich1334)
It asked for u and sigma

u=146 and sigma=2, right?
4. (Original post by rich1334)
For the doctor question, did you all reject H0? I got mean 11.76, variance 18 (unbiased estimator) and a z value of 1.92 or something like that
Yup, I got that too
5. (Original post by Molly_xox)

u=146 and sigma=2, right?

I recognise 146 so yeah I think so!
6. (Original post by Molly_xox)

u=146 and sigma=2, right?
yep i edited my post saying Var=4, hope i didnt worry too many people i just forgot what the question was
7. (Original post by tokopoko)
yep i edited my post saying Var=4, hope i didnt worry too many people i just forgot what the question was
Haha, no worries, it just would've been frustrating if we'd lost such a stupid mark
8. What did everyone get as the value for a for each part of the questions? I got a=6 for both....
9. I stored all my answers in my calculator and here they are (I think 8ii is wrong):
1. Mean = 146, sigma = 2
2. i) The rabbits occur independent of each other
ii) 0.222 (Using poisson)
3. i) a = 6
ii) a = 1.5
4. 0.8311
5. 0.2536
6. 0.9807
7. i) 0.1247
ii) 38
8. i) 0.0316
ii) 0.961 (I did 1 - (1/3((1-0.9685)+(1-0.6047)+(1-0.0933)))^4)
10. What did everyone get for 7ii)? Most people I've talked to either put 37 or 38.
11. (Original post by AMDD)
What did everyone get as the value for a for each part of the questions? I got a=6 for both....
a=6 for first part

i got a=1.5 for the second part (may be wrong though)
12. (Original post by TingA)
What did everyone get for 7ii)? Most people I've talked to either put 37 or 38.
38
13. (Original post by thickmaster)
I stored all my answers in my calculator and here they are (I think 8ii is wrong):
1. Mean = 146, sigma = 2
2. i) The rabbits occur independent of each other
ii) 0.222 (Using poisson)
3. i) a = 6
ii) a = 1.5
4. 0.8311
5. 0.2536
6. 0.9807
7. i) 0.1247
ii) 38
8. i) 0.0316
ii) 0.961 (I did 1 - (1/3((1-0.9685)+(1-0.6047)+(1-0.0933)))^4)
looks good from what i remember. 8ii) is wrong i think but you got method marks for using 0.6047 and 0.0933
14. (Original post by TingA)
What did everyone get for 7ii)? Most people I've talked to either put 37 or 38.
It's 38, I didn't know which way to round so I carried out the test on 37, 38 and 39 and 39 is the first one you do not reject.
15. (Original post by TingA)
What did everyone get for 7ii)? Most people I've talked to either put 37 or 38.
(Original post by tokopoko)
38
I got 37, you need to round down. I remember testing the different values and 38 didn't fall in the critical region
16. I did the test for 38 and got that you do not reject it. Did you remember continuity correction?
(Original post by Molly_xox)
It's 38, I didn't know which way to round so I carried out the test on 37, 38 and 39 and 39 is the first one you do not reject.
17. What do you think the grade boundary will be this year?
18. (Original post by Molly_xox)
It's 38, I didn't know which way to round so I carried out the test on 37, 38 and 39 and 39 is the first one you do not reject.
Did you apply a continuity correction?
19. (Original post by rich1334)
I got 37, you need to round down. I remember testing the different values and 38 didn't fall in the critical region
my critical region was about X<38.3. did you use a normal dist? so the biggest number in this region is 38
20. (Original post by rich1334)
I did the test for 38 and got that you do not reject it. Did you remember continuity correction?
Yeah, +0.5...

38-50/sq rt(50) = -1.697, and I thought you needed to compare it to -1.645?

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