Consumer Reports tested 14 brands of vanilla yogurt and found the following numbers of calories per serving: 160, 200, 220, 230, 120, 180, 140, 130, 170, 190, 80, 120, 100, and 170.

a) Check the assumptions and conditions for inference.

b) Create a 95% confidence interval for the average calorie content of vanilla yogurt.

c) A diet guide claims that you’ll get 120 calories from a serving of vanilla yogurt. What does this evidence indicate? Use your confidence interval to test an appropriate hypothesis and state your conclusion.