CHAPTER 1 Homework Solutions Problems 15, 21, 25

15. a. Quantitative – number of new drugs approved b. Time series from 1996 to 2003 c. 18 d. 2002; 16 new drugs e. Over the eight-year period, the number of new drugs approved by the FDA declined. From approximately 50 new drugs approved in 1996, the most recent years are showing only 16 to 18 new drugs approved.

21. a. The two populations are the population of women whose mothers took the drug DES during pregnancy and the population of women whose mothers did not take the drug DES during pregnancy. b. It was a survey. c. 63 / 3.980 = 15.8 women out of each 1000 developed tissue abnormalities. d. The article reported “twice” as many abnormalities in the women whose mothers had taken DES during pregnancy. Thus, a rough estimate would be 15.8/2 = 7.9 abnormalities per 1000 women whose mothers had not taken DES during pregnancy. e. In many situations, disease occurrences are rare and affect only a small portion of the population. Large samples are needed to collect data on a reasonable number of cases where the disease exists.

25. a. There are five variables: Exchange, Ticker Symbol, Market Cap, Price/Earnings Ratio and Gross Profit Margin. b. Categorical variables: Exchange and Ticker Symbol Quantitative variables: Market Cap, Price/Earnings Ratio, Gross Profit Margin c. Exchange variable: Exchange | Frequency | Percent Frequency | AMEX | 5 | (5/25) 20% | NYSE | 3 | (3/25) 12% | OTC | 17 | (17/25) 68% | | 25 | |