The Nielsen Company is an information, data, and market measurement firm that endeavors to provide its clients with valuable insights into consumer behavior and marketing information by collecting data that measures what consumers watch and what they buy. For example, the company publishes information on the TV-viewing habits of Americans in the Nielsen Report on Television. A random sample of 7 people yielded the weekly viewing times, in hours, is shown in the data set below. Calculate the sample standard deviation, s , representing the spread of the data set. 68 , 22 , 32 , 29 , 32 , 15 , 18