4. You are a registered nurse working in a weight loss clinic, and you have collected data on weight loss achieved by your clients who have undertaken various diets over a 6-week period. You collected background data on sex (0=females, 1=males), weight at the start of the diet (pre_wt, kg), weight at the end of 6 weeks (post_wt, kg), and other demographic variables. The complete date set is in the Data folder in A21 Contents, is called Q8_DIET. Note that the data set has some missing data (sex is missing for first 2 observations ), as commonly occurs in the real world . Use these data to answer the questions below . a. Conduct the appropriate statistical test to determine whether weight loss is the same in females and males . Assume that weight loss is normally distributed with equal variance in both sexes, and a = 0.05. Show all calculations. [2 Marks ] b. Calculate the 95% confidence interval for the mean difference in weight loss between the sexes. Show your calculation. [1 Mark ] c. Calculate the 99% confidence interval for the mean difference in weight loss between the sexes. Show your calculation. [1 Mark ]