Question

A diet claims to help lose weight. A dietician wants to see if a particular diet helps lose weight. 120 people were on the diet for 6 months. After 6 months, the sample mean of weight loss was 0.8 pound with sample SD of 2 pounds. The distribution is more or less normal. What kind of hypothesis testing do we use

Answer 1

d. t-test for means

Explanation:

Options are "a. z-test for proportions, b. z-test for means, c. none of the other three answers, d. t-test for means"

Sample size = n = 120

Sample mean = x = 0.8

Sample standard deviation = s = 2

Claim: A particular diet helps loss weight.

Hypothesis test

The null and alternative hypothesis is

H0 : μ = 0

Ha : μ < 0

Now, when population standard deviation is unknown we use t-test otherwise use z-test. So, the kind of hypothesis testing that we use is t-test for means.