Recall that the mean of a given set of numbers is the sum of the numbers divided by the number of numbers, therefore, the mean of the dataset is:
Now, the range of a data set is the difference between the maximum and the minimum, in this case, the maximum is 99, and the minimum is 15 therefore, the range is:
Finally, the standard deviation is given by the following formula:
where N is the sample size, x_i is an element of the set, and x^- is the mean. The standard deviation of the set is:
Answer: