Determine the (a) sample variance and (b) sample standard deviation for the preparation-time data in Problems 4.7 using the alternative computational formulas. Problem 4.7 A work-standards expert...

Determine the (a) sample variance and (b) sample standard deviation for the preparation-time data in Problems 4.7 using the alternative computational formulas.

Problem 4.7

A work-standards expert observes the amount of time required to prepare a sample of 10 business letters in an office with the following results listed in ascending order to the nearest minute: 5, 5, 5, 7, 9, 14, 15, 15, 16, 18.