This preview shows pages 1–4. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: C HAPTER 11 T WO S AMPLE T ESTS OF H YPOTHESIS 1. a. Twotailed test b. Reject H o if z <  2.05 or z > 2.05 c. 2.59, found by 2 2 102 99 5 6 40 50 z = + d. Reject H o and accept H 1 e. p = 0.0096, found by 2(0.5000 0.4952) This pvalue shows there is a very small chance of finding a z statistic this extreme when the null hypothesis is true. 2. a. Onetailed test b. Reject H o and accept H 1 if z > 1.41 c. 0.607 found by 2 2 2.67 2.59 (0.75) (0.66) 65 50 z = + d. Fail to reject H o e. p = 0.2709, found by 0.5000 0.2291 This pvalue shows there is a very large chance of finding a z statistic this extreme when the null hypothesis is true. 3. Step 1: H o : 1 2 H 1 : 1 < 2 Step 2: The 0.05 significance level was chosen Step 3: Reject H o and accept H 1 if z <  1.65 Step 4: 0.94, found by 2 2 7.6 8.1 (2.3) (2.9) 40 55 z = + Step 5: Fail to reject H o . Babies using the Gibbs brand did not gain less weight. p = 0.1736 found by 0.5000 0.3264 4. Step 1: H o : c = p H 1 : c p Step 2: The 0.05 significance level was chosen Step 3: Reject H o and accept H 1 if z less than  1.96 or greater than 1.96 Step 4: 1.53, found by 2 2 370 380 (30) (26) 35 40 z = + Step 5: Fail to reject H o . There is no difference in the mean number of miles traveled per month. The pvalue is 0.126 found by 2(0.5000 0.4370) Chapter 11 98 5. Twotailed test. Because we are trying to show a difference exists between two means. Reject H o if z <  2.58 or z > 2.58 2.66, found by 2 2 31.4 34.9 (5.1) (6.7) 32 49 z = + Reject H o at the 0.01 level. There is a difference in the mean turnover rate. The pvalue is 0.0078 found by 2(0.5000 0.4961). 6. H o : 1 2 H 1 : 1 > 2 If z > 2.05, reject H o . 2 2 20.75 19.80 2.09 (2.25) (1.90) 40 45 z = = + Reject the null. It is reasonable to conclude union nurses earn more. The pvalue is 0.0183. This pvalue shows there is a moderate chance of finding a z statistic this extreme when the null hypothesis is true. 7. a. H o is rejected if z > 1.65 b. 0.64, found by 70 90 100 150 c p + = + c. 1.61, found by 0.70 0.60 (0.64)(0.36) (0.64)(0.36) 100 150 z = + d. H o is not rejected 8. a. H o is rejected if z <  1.96 or z > 1.96 b. 0.80, found by 170 110 200 150 c p + = + c. 2.70, found by 0.85 0.7333 (0.80)(0.20) (0.80)(0.20) 200 150 z = + d. H o is rejected 9. a. H o : 1 = 2 H 1 : 1 2 b. H o is rejected if z <  1.96 or z > 1.96 c. 24 40 0.08 400 400 c p + = = + d. 2.09, found by 0.06 0.10 (0.08)(0.92) (0.08)(0.92) 400 400 z = + e. H o is rejected. The proportion infested is not the same in the two fields. Chapter 11 99 10. a. H o : 1 2 H 1 : 1 < 2 b. H o is rejected if z <  1.65 1530 2010 0.59 3000 3000 c p + = = + c. 12.60, found by 0.51 0.67 (0.59)(0.41) (0.59)(0.41) 3000 3000 z = + d. H o is rejected. The proportion of women who think men are thoughtful has declined....
View Full
Document
 Spring '08
 HALEY

Click to edit the document details