At the 0.05 significance level, can a physician conclude that there is a difference in the mean amount of weight loss among the three diets?

A physician who specializes in weight control has three different diets she recommends. As an experiment, she randomly selected 15 patients and then assigned five to each diet. After three weeks the following weight losses, in pounds, were noted.

Plan A 5,7,4,5,4
Plan B 6,7,7,5,6
Plan C 7,8,9,8,9?