1.Listed below are the distances (m) recorded in a Shot Put competition.

18.4, 17.6, 15.4, 21.1, 13.4, 14.5, 14.3, 12.8, 19.3, 12.5, 15.4

What percent of the distances are represented by the upper quartile?

2.The grades on a test follow a normal distribution with a mean mark of 70 and a standard deviation of 9.

Fred's mark is 75.What percentile is he in?

3.A study of 100 patients with back pain reported that the mean duration of pain was 12 months.It is known that the standard deviation of duration of back pain is 6.8 months.Assuming that the duration of this problem is normally distributed in the population; determine a 95% confidence interval for themean duration of back pain in the population.