Researchers recruited 18 healthy and normal-weight adults and for a four-week period increased their calorie intake and limited their daily activity. Not surprisingly, weight and body fat of the participants went up significantly during the study and then decreased after the study ended. However, two and a half years after the experiment, the mean weight gain for participants was 6.8 lbs with a standard error of 1.2 lbs.

a. Clearly define the relevant parameter in the context of the situation. Use correct notation.

b. What would you have to do to find the actual exact value of the parameter? Is that possible?

c. Assuming you were going to construct a 95% confidence interval, find the margin of error using the information given in the problem.

d. Use the margin of error to find a 95% confidence interval for the parameter and interpret it in context.