1. A diet doctor claims that the average North American is more than 20 pounds overweight. To test her claim, a random sample of 20 North Americans was weighed, and their actual weight subtract their ideal weight was calculated. The data is listed below: 29 marks

16 23 18 41 22 18 23 19 22 15

18 35 16 15 17 19 23 15 16 26

The sample statistics are: = 20.85, = 6.76.

Can we infer, at the 5% significance level, that the doctor's claim is true? Assumethe required conditions are satisfied.

H0 : = 20

H₁ : > 20

Conclusion: Reject H₀ Do not reject H₀

Reason for conclusion:there is not enough evidence to support the claim that the average North American is more than 20 pounds overweight at the 5% significance level.

What are the required conditions for this test?