3. Given the following GPA for 4 students: 2, 3, 3, 4. Age of students are: 10, 11, 12, 15. There are 10,000 total students. Average GPA: Unknown, Standard Deviation of GPA: 0.02 and it's Normal. a. Find the mean and standard deviation for GPA. b. Calculate a 95% confidence interval for the populations mean GPA

We are going to calculate the standard deviation for the following set of sample data. 13,9,11,13,5 1) First, calculate the mean. 2) Fill in the table below. Fill in the differences of each data value from the mean, then the squared differences. 3) Calculate the standard deviation. (x – a)² 13 9 11 13 Total Standard deviation: - Round to two decimal places S = п — 1

Cholesterol The level of cholesterol in the blood for all men aged 20 to 34 follows a Normal distribution with mean 188 milligrams per deciliter (mg/dl) and standard deviation 41 mg/dl. For 14-year-old boys, blood cholesterol levels follow a Normal distribution with mean 170 mg/dl and standard deviation 30 mg/dl. Suppose we select independent SRSs of 25 men aged 20 to 34 and 36 boys aged 14 and calculate the sample mean cholesterol levels M and XB. What is the shape of the sampling distribution of XM - XB? Why? Find the mean of the sampling distribution. Show your work. Find the standard deviation of the sampling distribu- tion. Show your work.

if the class average is 84 with a standard deviation of 5. what is the percentil rank for a score of 94 ?