Stock returns vary from year to year. The more variance a stock displays the greater the potential risk. These are the
rates of return for a stock over the last five years. Calculate the variance of these investment returns: 10, 30, 15, 5, 20. Hint: The variance of
a series of numbers is the sum of the squares of their differences from the mean (average) of the numbers divided by the number of items
in the series.
a) 21
b) 53
c) 74
d) 95