In certain drug trial, 10 subjects who received a placeboreported headaches, while 30 subjects who received a placeboreported no headaches. Of the subjects taking a new drug, 20reported headaches, while 30 did not. a) Display this informationin a contingency table, including all totals. b) What percentage ofparticipants in the trial reported headaches? c) What percentage ofnew-drug takers reported headaches? d) What percentage of placebotakers reported headaches?

a) Draw a diagram to show a standard Normal distribution andshade in the regions between (µ–3(sigma)) and (µ+(sigma)). Find theapproximate percentage of the population that would have values inthis region. b) A researcher has found that among many mice ingiven maze the average time to complete the circuit is 10 minutes.The times were normally distributed with a standard deviation of 3minutes. Find: i) the approximate proportion of mice that completedthe maze in less than 4 minutes, ii) the probability that a randommouse takes more than 15 minutes to complete the maze, iii) thetime to complete the maze below which are the fastest 5% of mice,and iv) the first quartile of the times to complete the maze

Use the following stem-and-leaf display of the ages of 10persons.

1 | 2 4 4

2| 1 1 2 6 9

3| 2

4|

5 | 8

a) Find the mean and mode of the ages. b) By hand, find thefive-number summary of the ages. c) Find the range andinterquartile range of the ages. d) Provide a dot plot of theages.