Twenty women were given a pharmaceutical prearation for several weeks and each woman's change in body weight was recorded. It...

Twenty women were given a pharmaceutical prearation for several weeks and each woman's change in body weight was recorded. It is found that the mean change in body weight was -1.1 kg (i.e., there was a mean weight loss of 1.1 kd). For a purpose of this exercise, let us say that we know that the twenty data came from a population of weight changes that had a variance of 7.79 kg^2. State the appropriate null and alternative hypotheses, and perform the appropriate statistical test for each of these three situations