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Hypothesis Testing

Hi, i was hoping to get help with this question:
Miss Cackle wishes to decrease the percentage of pupils giving up her potion-
making class after year 9 from its current level of 20%. Over the last 3 years she
has tried a new teaching method in one of her classes of 30 pupils, Using a 10%
significance level find the critical region for a test of whether the number of
pupils giving up potions after year 9 has decreased. State the actual significance
level.
Reply 1
Original post by ursoannoy
Hi, i was hoping to get help with this question:
Miss Cackle wishes to decrease the percentage of pupils giving up her potion-
making class after year 9 from its current level of 20%. Over the last 3 years she
has tried a new teaching method in one of her classes of 30 pupils, Using a 10%
significance level find the critical region for a test of whether the number of
pupils giving up potions after year 9 has decreased. State the actual significance
level.

What have you done so far / what are you stuck with?
Reply 2
Original post by mqb2766
What have you done so far / what are you stuck with?

I'm not sure on how to set out my answer so I'm really stuck on how to approach it and what to do T_T
Reply 3
Original post by ursoannoy
I'm not sure on how to set out my answer so I'm really stuck on how to approach it and what to do T_T

Is it one tailed or two tailed, what distribution, ...?
Reply 4
Original post by mqb2766
Is it one tailed or two tailed, what distribution, ...?

I'm presuming it's a one tail test as she's trying to see if the number of pupils had decreased?
Reply 5
Original post by ursoannoy
I'm presuming it's a one tail test as she's trying to see if the number of pupils had decreased?

Agreed, so what is the actual test/level?
And as in the the previous post, which distribution and what are the parameters?
(edited 2 weeks ago)
Reply 6
Original post by mqb2766
Agreed, so what is the actual test/level?
And as in the the previous post, which distribution and what are the parameters?

so the binomial distribution would be X~B (30, 0.15)
the null hypothesis is p=0.15
and H1: p<0.15
(edited 2 weeks ago)
Reply 7
Original post by ursoannoy
so the binomial distribution would be X~B (30, 0.15)
the

Why 0.15?
Reply 8
Original post by mqb2766
Why 0.15?

sorry, is it 0.2?
Reply 9
Original post by ursoannoy
sorry, is it 0.2?

Of course. You must have several similar examples to this in your textbook and you should be able to write this down (even with the odd error) without me having to prompt you.

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So again, what is the test that youre performing

ā€¢

How is this stated in terms of a (cumulative) probability for the binomial distribution

ā€¢

What numbers do you get from your calcuator when you put the previous two things together and the question asks you both for the critical region and the actual significance. The actual significance may differ a bit from the stated one as its a discrete distribution.

Reply 10
Original post by mqb2766
Of course. You must have several similar examples to this in your textbook and you should be able to write this down (even with the odd error) without me having to prompt you.

ā€¢

So again, what is the test that youre performing

ā€¢

How is this stated in terms of a (cumulative) probability for the binomial distribution

ā€¢

What numbers do you get from your calcuator when you put the previous two things together and the question asks you both for the critical region and the actual significance. The actual significance may differ a bit from the stated one as its a discrete distribution.


maybe I should have made myself more clear from the start, I had actually already figured out the distribution and hypothesis for the question as that is how you always approach these. But my main issue with the question is how to calculate the critical region so please can you explain that to me? Also the 'odd error' i made was because I was looking at a previous example I had done.
Original post by ursoannoy
maybe I should have made myself more clear from the start, I had actually already figured out the distribution and hypothesis for the question as that is how you always approach these. But my main issue with the question is how to calculate the critical region so please can you explain that to me? Also the 'odd error' i made was because I was looking at a previous example I had done.

Can you upload what you have done then, so I can see what you think the test is etc.
Original post by ursoannoy
Hi, i was hoping to get help with this question:
Miss Cackle wishes to decrease the percentage of pupils giving up her potion-
making class after year 9 from its current level of 20%. Over the last 3 years she
has tried a new teaching method in one of her classes of 30 pupils, Using a 10%
significance level find the critical region for a test of whether the number of
pupils giving up potions after year 9 has decreased. State the actual significance
level.

WAIT are u from sg ??? šŸ˜­šŸ˜­šŸ˜­šŸ˜­

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