Question: A group of medical researchers is interested in knowing the mean cholesterol level for all men in the U.S. aged between 70 and 80. They pick a sample of 5,000 men and measure their cholesterol levels. They then calculate the mean and standard deviation of these cholesterol levels.

a) Do the mean and standard deviation obtained in this way represent parameters or statistics? Why? What symbols could you use to denote the mean and standard deviation of the 5,000 cholesterol levels?

b) Suppose the researchers construct a frequency histogram of their data and it is skewed to the right. What conclusion can you draw about the distribution of cholesterol levels for all men between 70 and 80? Why?