Use your class as a sample. Determine the mean, median, and standard deviation for the age of students in your class. What z score would a 40-year-old have? Would it be unusual to have an age of 40? Determine the skew of the data, using the Pearson coefficient of skewness. 

Data from in Exercise 48 of exercise 3.2

A measure to determine the skewness of a distribution is called the Pearson coefficient (PC) of skewness. The formula is

The values of the coefficient usually range from 3 to +3. When the distribution is symmetric, the coefficient is zero; when the distribution is positively skewed, it is positive; and when the distribution is negatively skewed, it is negative. Using the formula, find the coefficient of skewness for each distribution, and describe the shape of the distribution.
a. Mean = 10, median = 8, standard deviation = 3.
b. Mean = 42, median = 45, standard deviation = 4.
c. Mean = 18.6, median = 18.6, standard deviation = 1.5.
d. Mean = 98, median = 97.6, standard deviation = 4.

PC 3(X - MD) S