Question

QUICK is 12.5 to 11.1. Using the confidence interval give (a) A 95% confidence intervalfor a mean (b) A 90% confidence interval for a proportion p is 0.62 to 0.80. Testing Ho: p=0.65 vs H.: p=0.65. (c) A 99% confidence intervalfor a difference in proportions is - 0.10 to 0.20. Testing Ho: P = P2 vs Ho: P. #P2. Example 3: Evaluating Drugs to Fight Cocaine Addiction In a randomized experimenton treating cocaine addiction, 48 cocaine addicts who were trying to quit were randomly assigned to take either desipramine (a new drug), or Lithium (an existing drug). The response variable is whether or not the person relapsed (which means the person was unable to break out of the cycle of addiction and returned to using cocaine.) We are testing to see if desipramine is better than lithium at treating cocaine addiction. The results are shown in the two-way table. Relapse No relapse Total Desipramine 10 24 Lithium 18 6 24 Total 28 48 (a) Using po for the proportion of desipramine users who relapse and for the proportion of lithium users who relapse, write the null and alternative hypotheses. (Example continued on reverse.) 14 20

Answer 1

3. H0 : there is no significant difference in both drugs

H1: There is significant difference in both drugs

Test statistic

Chi square:

Marginal Row Totals 24 Desipramine Lithium Marginal Column Totals Relapse 10 (14) (1.14 18 (14) [1.14 28 No relapse 14 (10) [1.6] 6 (10) [16] 20 24 48 (Grand Total) The chi-square statistic is 5.4857. The p-value is .019172. Significant at p<.05. The chi-square statistic with Yates correction is 4.2. The p-value is .040424. Significant at p<.05.