3. (20pts)Let us presume that we want to know what the average cholesterol concentration in the population is. To answer this question we select a sample fo_r which we believe t represents the population and in this sample, we calculate the mean of cholesterol concentration. By random selection we have sampled 1,211 people (n=1211) and determine the mean of cholesterol concentration: 6.9 i 1.5 mmol/L (sample mean i sample standard deviation)