S2 OCR june 2014 (not mei) thread

Thought the integration of sin was sly!

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Questions I dun goofed

Probability density : making q the lower limit

Finding sd and mean on the interval question. It was half done

The question saying by considering the amount of people that did not attend

Some wordy questions

Few more

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Damn it! I put q= pi/3. Rookie mistake.

Apart from that it was ok. Unless there were any other stupid mistakes like that I think I got everything else.

For the central limit Q I said a normal dist was needed for the first part but not the second.

Definitely didn't get 9.84% for part 8i...

2.73%?

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You were supposed to make q the lower limit on the probability density question - you had to set the integral of f(x) between 1 and q to equal 0.75. If you didn't get q = 1/3, you must have done something else wrong.

There's one question I'm not sure about.


When it asked whether the normal assumption was necessary for the previous two parts of the question, I gave a very vague explanation for why it was necessary in the first part - I think I said something along the lines of "Yes, as the calculation relied on it having a normal distribution."

Do you think that would cost me a mark?

I skimped on that part as I thought the focus would be on the second, saying no because n was large so CLT could be used.

Do you think you'd still get full method marks for doing the integral between 0 and q and making it equal to 0.25?



I really couldn't say. How many marks was it out of? I thought the question itself was "Is a normal approximation needed".
EDIT: Oh, and speaking of marks, how much was 8i? Just two?

Do you think you'd still get full method marks for doing the integral between 0 and q and making it equal to 0.25?

I really couldn't say. How many marks was it out of?
EDIT: Oh, and speaking of marks, how much was 8i? Just two?

Anyone say that when the test was carried out at a 10% sig level, it supported the managers claim
lol the paper suggested they were racist!)

You only had to say if it would have an increased chance of supporting the managers claim/increase the chance that the manager was right.

The answer is yes because the probability of rejecting H0 was higher (0.05 > 0.1). I may have messed up the wording in exam (for some reason I talked about type 1 errors ugh) but the general idea was right.

There's one question I'm not sure about.


When it asked whether the normal assumption was necessary for the previous two parts of the question, I gave a very vague explanation for why it was necessary in the first part - I think I said something along the lines of "Yes, as the calculation relied on it having a normal distribution."

Do you think that would cost me a mark?

I skimped on that part as I thought the focus would be on the second, saying no because n was large so CLT could be used.

I'm pretty sure you were supposed to use the test statistic (0.0834 or w/e it was) from the previous part and show that H0 would have been rejected at a 10% significance level.

I said "the calculation is dependent on the distribution of the underlying parent population of candidates and therefore we must know this distribution, i.e. that it is normal, to proceed". I'm not sure yours is enough but "Yes" will count for something on its own.

Also, what did you put for the "why is it only an estimate" question?

I remember getting 0.0661 rather than 0.0662 for the 7i.). Do you remember the questions for q4 and 7?

Do you think it would be enough to say "At the 10% significance level H0 is rejected and so using this level supports the mananger's claim"? Or do you have to specifically write 0.0834<0.10, because I didn't