A medical researcher believes that a drug changes the body's temperature. Seven test subjects are randomly selected and the body temperature of each is measured. The subjects are then given the drug, and after 30 minutes, the body temperature of each is measured again. The results are listed in the table below. Is there enough evidence to conclude that the drug changes the body's temperature?

Let d=(body temperature after taking drug)−(body temperature before taking drug) . Use a significance level of α=0.05 for the test. Assume that the body temperatures are normally distributed for the population of people both before and after taking the drug.
Subject Temperature (before) Temperature (after) 1 99.7 99.1 2 100.6 99.8 3 98.8 99.7 4 99.2 99 5 99.4 98.7 6 99.1 98.3 7 99 98.5 Step 1 of 5 : State the null and alternative hypotheses for the test.