Fall Semester 2002

1. If the time required to appreciate this work of art (Paul Klee, The Beautiful Flowerpot) before writing an essay on it is believed to be distributed normally, with a mean of 65 minutes and a standard deviation of 15 minutes, then how long should an examination be so that 99% of those taking can finish writing about it in time?

2. In the early 1980s the Toro Company of Minneapolis, Minnesota, advertised that it would refund the purchase price of a snowblower if the following winter's snowfall was less than 21 percent of the local average. If the average snowfall is 45.25 inches, with a standard deviation of 12.2 inches, what is the likelihood that Toro will have to make refunds.

3. When workers are paid by the piece, the average time required to complete the task is usually well publicized by the employer. Suppose that a time study shows that a task takes 2.4 minutes to complete, on the average, with a standard deviation of 0.6 minute. If time of task is normally distributed, how often is the task completed in one to three minutes.

4. The Wall Street Journal (February 26, 1992) reported that in 1990 the job average tenure of marketing directors at law firms was 2.1 years but that one-third had been on the job for a year or less. The question: Could marketing director tenure be approximately normally distributed?