Turn on thread page Beta
 You are Here: Home >< Maths

# Hypothesis test watch

1. Dhriti grows tomatoes. Over a period of time, she has found that there is a probability 0.3
of a ripe tomato having a diameter greater than 4 cm. She decides to try a new fertiliser. In
a random sample of 40 ripe tomatoes, 18 have a diameter greater than 4 cm. Dhriti claims
that the new fertiliser has increased the probability of a ripe tomato being greater than
4 cm in diameter.
Test Dhriti’s claim at the 5% level of significance. State your hypotheses clearly.

H0: p = 0.3
H1: p > 0.3

Why is the next line

P(X>= 18) NOT P(X<=18)

thanks
2. 0.3*40 = 12.

So 18 is larger than expected so you are looking for 18 or even greater than 18.

If you had an answer smaller than 12 it would be 'less than or equal to'.
3. why?
4. (Original post by jsmith6131)
why?
What does H1 say?

It basically says if p =/= 0.3, then it must be >0.3 because there were so many large tomatoes.

What we require, is the probability of getting 'as bad or worse' as this. That means 18 tomatoes or even more than 18. If the probability of that is so small (under 5%) then it can be said it is so rare that chances are, p>0.3 and we take H1.

The result can be thought of as a 'rare outlier' if you will. And we need the probability of it being even rarer or just as rare as that. So if it is under the expected value we look to less than, but when it is more than the expected value we are looking at more than.
5. thanks

Turn on thread page Beta
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: December 3, 2011
Today on TSR

### Are exams rubbish?

Is the exam system out of date?

### University open days

• University of Exeter
Undergraduate Open Days - Exeter Campus Undergraduate
Wed, 24 Oct '18
• University of Bradford
Faculty of Health Studies Postgraduate
Wed, 24 Oct '18
• Northumbria University
Wed, 24 Oct '18
Poll
Useful resources

## Make your revision easier

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

Can you help? Study help unanswered threads

## 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