Question

(1 point) In 2002 the Supreme Court ruled that schools could require random drug tests of students participating in competitive after-school activities such as athletics. Does drug testing reduce use of illegal drugs? A study compared two similar high schools in Oregon. Wahtonka High School tested athletes at random and Warrenton High School did not. In a confidential survey, 8 of 110 athletes at Wahtonka and 29 of 102 athletes at Warrenton said they were using drugs. Regard these athletes as SRSs from the populations of athletes at similar schools with and without drug testing. (a) You should not use the large-sample confidence interval. Why not? The sample sizes are too small. (b) The plus four method adds two observations, a success and a failure, to each sample. What are the sample sizes and the numbers of drug users after you do this? Wahtonka sample size: Wahtonka drug users: Warrenton sample size: Warrenton drug users: (c) Give the plus four 99.9% confidence interval for the difference between the proportion of athletes using drugs at schools with and without testing. Interval:

Answer 1

salesian from the given data: at In a confidential Survey & at to athletes wohtonka and za af loz athletes at warrentiam were using drugs. said they wahtonka sample size = 110+2 -112 wahdenka drug users = 8+1=9 Warrenton Sample Size 129+2 3131. warrenton drog Users 29+1 230. c) Here we have to find 99,9% confidence interval CI= (pa-) + Pan Pi (1-P) + P. Il- P3) 99,9% is 3.291. 2 - Coil'cal value for given from above (6) h = od 0.219 5 0.25 0.08(1-0.08) 3.291 / 112 * 0.23 (1-0.23) C.I 2 (0.08-0.28) 131

Ci I: -0.15 + 3.291 0.0736 0.0136 01971 t 112 BE 2 -0.15 + 3.291 10 044822941) > -0.16 A 0:1475 Head = (-0.2975, -0.0025) C.I60.30,-0.00) or