Question 1 Fitness experts advise people who want to lose weight to drink protein shakes after workout sessions, because it helps build muscle mass and speeds up the weight-loss process. To test the effectiveness of protein shakes in losing weight, 200 adults between the ages of 25 and 40 years were divided equally into two groups: a treatment group and a control group. The treatment group was asked to drink a protein shake after every workout session for a period of 6 months. The subjects’ weights were noted before and after the treatment.

The results showed that the mean change in the amount of weight lost by the treatment group is 8 points more than that of the control group. To test whether the results could be explained by random chance, researchers created a table that summarizes the results of 1,000 re-randomizations of the data with differences of means rounded to the nearest 2 points.

Consider the significance level to be set at 5%, so results less than 5% can be considered statistically significant.