Chapter II

Over a period of years, toothpaste has received a mean rating of 5.9, on a 7-point scale, for overall customer satisfaction with the product, Because of a minor unadvertised change in the product, there is concern that the customer satisfaction may have changed. Suppose the satisfaction ratings from a sample of 60 customers have a mean of 5.60 and a standard deviation of 0.87. Do these data indicate that the mean satisfaction rating is different from 5.9? Test with =0.05.