Vegetarians' Weights
The mean weight of all 20-yearold women is 128 pounds .
A random sample of 40 vegetarian women who are 20 years old showed a sample mean of 122 pounds with a standard deviation of 15 pounds.
The women's measurements were independent of each other.
a. Determine whether the mean weight for 20-year old vegetarian women is significantly less than 128, using a significance level of 0.05.
b. Now suppose the sample consists of 100 vegetarian women who are 20 years old, and repeat the test.
c. Explain what causes the difference between the p-values for parts a and b.