You are Here: Home >< Maths

# How should I solve this question in 9709/71

Announcements Posted on
TSR's new app is coming! Sign up here to try it first >> 17-10-2016
1. May/June 2015 Paper-71
Question 2
Sami claims that he can read minds. He asks each of 50 people to choose one of the 5 letters A, B, C, D or E. He then tells each person which letter he believes they have chosen. He gets 13 correct. Sami says “This shows that I can read minds, because 13 is more than I would have got right if I were just guessing.”
(i) State null and alternative hypotheses for a test of Sami’s claim. [1]
(ii) Test at the 10% signiﬁcance level whether Sami’s claim is justiﬁed. [5]
2. (Original post by Abinaya P L)
May/June 2015 Paper-71
Question 2
Sami claims that he can read minds. He asks each of 50 people to choose one of the 5 letters A, B, C, D or E. He then tells each person which letter he believes they have chosen. He gets 13 correct. Sami says “This shows that I can read minds, because 13 is more than I would have got right if I were just guessing.”
(i) State null and alternative hypotheses for a test of Sami’s claim. [1]
(ii) Test at the 10% signiﬁcance level whether Sami’s claim is justiﬁed. [5]
So, first of all, tell us what you have tried; the style in this forum is to help people along from where they've got stuck after they've had a go!

If you are completely stuck right at the beginning, think about what the probability is for Sami making a correct guess for any particular individual, and therefore write down the probability of him making an incorrect guess for that individual. What sort of trial is this usually called? Now string fifty of these guesses together; what is the probability distribution that is involved?
3. (Original post by Gregorius)
So, first of all, tell us what you have tried; the style in this forum is to help people along from where they've got stuck after they've had a go!

If you are completely stuck right at the beginning, think about what the probability is for Sami making a correct guess for any particular individual, and therefore write down the probability of him making an incorrect guess for that individual. What sort of trial is this usually called? Now string fifty of these guesses together; what is the probability distribution that is involved?
I know that Ho P:0.2
H1 P>0.2
But I dont understand from where 125 comes
Can you please provide me with an worked solution for this question
4. (Original post by Abinaya P L)
I know that Ho P:0.2
H1 P>0.2
H0 is fine, but are you sure about H1?

Can you please provide me with an worked solution for this question
What's the probability distribution you should be considering for the second part?
5. (Original post by Gregorius)
H0 is fine, but are you sure about H1?

What's the probability distribution you should be considering for the second part?
H1 P>0.2 right
Should the probability for second part be 0.26
Even if I try with 0.26, I don't know how to proceed with it

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: October 2, 2016
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:
Today on TSR

### How does exam reform affect you?

From GCSE to A level, it's all changing

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams