Question

The producer of a weight-loss pill advertises that people who use the pill lose, after one week, an average (mean) of 1.85 pounds with a standard deviation of 0.95 pounds. In a recent study, a group of 60 people who used this pill were interviewed. The study revealed that these people lost a mean of 1.73 pounds after one week. If the producer's claim is correct, what is the probability that the mean weight loss after one week on this pill for a random sample of 60 individuals will be 1.73 pounds or less?

Answer 1

n = 60

The test hypothesis is

This is a one-sided test because the alternative hypothesis is formulated to detect the difference from the hypothesized mean on the upper side
Now, the value of test static can be found out by following formula:

Since the sample size is n = 60, degrees of freedom on the t-test statistic are n-1 = 60-1 = 59
This implies that

Since t, we fail to reject the null hypothesis