Chapter 7 Even - Inferences Based on Two Samples Confidence...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Inferences Based on Two Samples: Confidence Intervals and Tests of Hypothesis Chapter 7 7.2 a. 1 x μ = μ 1 = 12 1 1 1 4 64 x n σ σ = = = .5 b. 2 x μ = μ 2 = 10 2 2 2 3 64 x n σ σ = = = .375 c. 1 2 x x μ = μ 1 μ 2 = 12 10 = 2 1 2 2 2 2 2 1 2 1 2 4 3 2 64 64 64 x x n n σ σ σ = + = + = 5 = .625 d. Since n 1 30 and n 2 30, the sampling distribution of 1 2 x x is approximately normal by the Central Limit Theorem. 7.4 Assumptions about the two populations: 1. Both sampled populations have relative frequency distributions that are approximately normal. 2. The population variances are equal. Assumptions about the two samples: The samples are randomly and independently selected from the population. 7.6 a. 2 p s = 2 2 1 1 2 2 1 2 ( 1) ( 1) (25 1)120 (25 1)100 5280 2 25 25 2 48 n s n s n n + + = = + + + = 110 b. 2 p s = (20 1)12 (10 1)20 408 20 10 2 28 + = + = 14.5714 c. 2 p s = (6 1).15 (10 1).2 2.55 6 10 2 14 + = + = .1821 d. 2 p s = (16 1)3000 (17 1)2500 85,000 16 17 2 31 + = + = 2741.9355 e. 2 p s falls near the variance with the larger sample size. Inferences Based on Two Samples: Confidence Intervals and Tests of Hypothesis 201
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon