49. Shaver Manufacturing Inc. offers dental insurance to its employees. A recent study by the human resource director shows the annual cost per employee per year followed the normal probability distribution, with a mean of$l,280 andastandard deviation ot$420 per year. a. What fraction of the employees cost more than $1,500 per year for dental expenses? It. What fraction of the employees cost between $1,500 and $2,000 per year? c . Estimate the percent that did not have any dental expense. (I. What was the cost for the 10 percent of employees who incurred the highest dental expense? 51. According to the South Dakota Department of Health, the mean number of hours of TV viewing per week is higher among adult women than men. A recent study showed women spent an average of 34 hours per week watching TV and men 29 hours per week. Assume that the distribution of hours watched follows the normal distribution for both groups, and that the standard deviation among the women is 4.5 hours and is 5.1 hours for the men. a. What percent of the women watch TV less than 40 hours per week? It. What percent of the men watch TV more than 25 hours per week? c. How many hours of TV do the one percent of women who watch the most TV per week watch? Find the comparable value for the men. 53. Management at Gordon Electronics is considering adopting a bonus system to increase production. One suggestion is to pay a bonus on the highest 5 percent of production based on past experience. Past records indicate weekly production follows the normal distribution. The mean of this distribution is 4,000 units per week and the standard deviation is 60 units per week. If the bonus is paid on the upper 5 percent of production, the bonus will be paid on how many units or more? 55. Best Electronics Inc. offers a "no hassle" returns policy. The number of items returned per day follows the normal distribution. The mean number of customer retmns is 10.3 per day and the standard deviation is 2.25 per d a y . a. In what percent of the days are there 3 or fewer customers returning items? I}. In what percent of the days are between 12 and 14 customers returning items? c. Is there any chance of a day with no returns