Statistical Sciences 1024A/B Chapter 21: Chapter+21

• School: Western University
• Department: Statistical Sciences
• Course: Statistical Sciences 1024A/B
• Professor: Jessica Kelly

Document Summary

21. 1: plan: we construct a 95% confidence interval for proportion of younger people that text often, and. Solve: we have two large samples: 625 younger people and 1917 older people. The number of successes in each sample (475 and 786, respectively) and the number of failures in each. 475 sample (150 and 1131) are large enough to use large-sample methods. 625 p2 denotes the proportion for older people. p1 p2, where p1 denotes the. 0. 76, and error for 95% confidence is 1. 96(0. 0204) = 0. 0400 and a 95% confidence interval for the difference in proportions is 0. 3100 to 0. 3900, or 31% to 39%. Conclude: with 95% confidence, the proportion of teenagers that text exceeds that of persons 18 and over by somewhere between 0. 31 and 0. 39. 21. 2: plan: we construct a 95% confidence interval for proportion of democrats that believe a person should be able to speak, and proportion of republicans that believe a person should be able to speak.