1. Using the following data:

23, 74, 18, 21, 20, 43, 56, 71, 73, 65, 34, 47, 51, 55, 56, 29

Calculate the starting and end point for the first interval.

2.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?

3.The thickness of ice at various locations on a frozen lake (in inches) can be represented by the normal distribution X~N(4.5, 0.25²)

What range of thickness does 68% of the ice fall between?

What percent of the ice is less than 4.2 inches thick?

What percent of the ice is between 4.4 inches and 5.1 inches thick?

What percent of the ice is more than 4.7 inches thick?

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

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

What mark does Fred need on the test to be in the 90^thpercentile?

6.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.

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