For healthy individuals fasting blood glucose levels are approximately normally distributed with a mean of 85 mg/dl and a standard deviation of 6.4mg/dl. Suppose random samples of size 20 healthy...

For healthy individuals fasting blood glucose levels are approximately normally distributed with a mean of 85 mg/dl and a standard deviation of 6.4mg/dl. Suppose random samples of size 20 healthy individuals are taken from the populatioN.

• The middle 90% of the mean are between what values ?[with n=20]

• Suppose a sample of 100 healthy individuals are selected for a study. What is the probability that their mean glucose level is between 84 and 86 mg/dl?