A study is run to estimate the mean total cholesterol level in children 2 to 6 years of age who have a family history of heart disease. A sample of thirteen participants is selected and their total cholesterol levels are measured as follows:

186, 200, 225, 243, 196, 188, 197, 175, 181, 194, 146, 223, 172

a) Is the outcome variable continuous or dichotomous? Why?

b) Calculate the point estimate (sample mean)for the total cholesterol level of the thirteen children 2 to 6 years of age.

c) Should a z or t value be used to construct a confidence interval? Explain reasoning.

d) Find the appropriate z or t value for a 95% confidence level.

e) Use Excel to calculate the variance of the total cholesterol levels for these thirteen participants.

f) Calculate the standard deviation of the total cholesterol levels for these thirteen participants from the variance in part (e). Show work.

g) Calculate the standard error of the average total cholesterol levels for these thirteen participants. Show work.

h) Determine the 95% confidence interval for the mean total cholesterol levels in this population. Show work.

i) Write out an interpretation of the confidence interval.