Bluman A.G. Elementary Statistics- A Step By Step Approach

Instructor’s Section Answers20. H 0 : m 12.4 and H 1 : m 12.4 (claim); t 2.324;C.V. 1.345; reject. There is enough evidence tosupport the claim that the average is less than thecompany claimed.21. H 0 : m 63.5 and H 1 : m 63.5 (claim); t 0.47075;P-value 0.25 (0.322); since P-value 0.05, do notreject. There is not enough evidence to support the claimthat the average is greater than 63.5.22. H 0 : m 26 (claim) and H 1 : m 26; t 1.5;C.V. 2.492; do not reject. There is not enoughevidence to reject the claim that the average is 26.23. H 0 : p 0.39 (claim) and H 1 : p 0.39; C.V. 1.96;z 0.62; do not reject. There is not enough evidence toreject the claim that 39% took supplements. The studysupports the results of the previous study.24. H 0 : p 0.55 (claim) and H 1 : p 0.55; z 0.8989;C.V. 1.28; do not reject. There is not enoughevidence to reject the survey’s claim.25. H 0 : p 0.35 (claim) and H 1 : p 0.35; C.V. 2.33;z 0.666; do not reject. There is not enough evidenceto reject the claim that the proportion is 35%.26. H 0 : p 0.75 (claim) and H 1 : p 0.75; z 2.6833;C.V. 2.58; reject. There is enough evidence to rejectthe claim.27. P-value 0.032428. P-value 0.000129. H 0 : s 6 and H 1 : s 6 (claim); x 2 54;C.V. 36.415; reject. There is enough evidence tosupport the claim.30. H 0 : s 8 (claim) and H 1 : s 8; x 2 33.2;C.V. 27.991, 79.490; do not reject. There is not enoughevidence to reject the claim that s 8.31. H 0 : s 2.3 and H 1 : s 2.3 (claim); x 2 13;C.V. 10.117; do not reject. There is not enoughevidence to support the claim that the standard deviationis less than 2.3.32. H 0 : s 9 (claim) and H 1 : s 9; x 2 13.4;P-value 0.20 (0.291); since P-value 0.05, do notreject. There is not enough evidence to reject the claimthat s 9.33. 28.9 m 31.2; no34. $6562.81 m $6637.19; noChapter 9Exercises 9–11. Testing a single mean involves comparing a sample meanto a specific value such as m 100; testing the differencebetween two means involves comparing the means of twosamples, such as m 1 m 2 .2. When both samples are larger than or equal to 30, thedistribution will be approximately normal. The mean ofthe differences will be equal to zero. The standarddeviation of the differences will bes 2 1 s2 2An 1 n 23. The populations must be independent of each other, andthey must be normally distributed; s 1 and s 2 can be usedin place of s 1 and s 2 when s 1 and s 2 are unknown, buta t test must be used.4. H 0 : m 1 m 2 or H 0 : m 1 m 2 05. H 0 : m 1 m 2 (claim) and H 1 : m 1 m 2 ; C.V. 2.58;z 0.88; do not reject. There is not enough evidence toreject the claim that the average lengths of the majorrivers are the same. (TI: z 0.856)6. H 0 : m 1 m 2 ; H 1 : m 1 m 2 (claim); C.V. 1.65;z 0.95; do not reject. There is not enough evidence toreject the claim that the means are different.7. H 0 : m 1 m 2 ; H 1 : m 1 m 2 (claim); C.V. 1.96;z 3.65; reject. There is sufficient evidence ata 0.05 to conclude that the commuting times differin the winter.8. 1.2363 m 1 m 2 6.6363. Yes, since the intervalcontains 0.9. H 0 : m 1 m 2 ; H 1 : m 1 m 2 (claim); C.V. 2.33;z 3.75; reject. There is sufficient evidence at a 0.01to conclude that the average hospital stay for men islonger.10. H 0 : m 1 m 2 (claim) and H 1 : m 1 m 2 ; C.V. 2.58;z 3.82; reject. There is enough evidence to reject theclaim that the average costs of the homes in bothlocations are the same.11. H 0 : m 1 m 2 and H 1 : m 1 m 2 (claim); C.V. 1.65;z 2.01; reject. There is enough evidence to supportthe claim that the stayers had a higher grade pointaverage.12. H 0 : m 1 m 2 and H 1 : m 1 m 2 (claim); C.V. 1.65;z 3.65; reject. There is enough evidence to supportthe claim that Ohio students are below the nationalaverage.13. H 0 : m 1 m 2 ; H 1 : m 1 m 2 (claim); C.V. 1.96;z 0.66; do not reject. There is not enough evidenceto support the claim that there is a difference in themeans.14. H 0 : m 1 m 2 30; H 1 : m 1 m 2 30 (claim); C.V. 1.645; z 1.52; do not reject. There is insufficientevidence to conclude that the difference in benefits isgreater than $30.15. H 0 : m 1 m 2 and H 1 : m 1 m 2 (claim); z 1.01;P-value 0.3124; do not reject. There is not enoughevidence to support the claim that there is a differencein self-esteem scores. (TI: P-value 0.3131)16. H 0 : m 1 m 2 (claim) and H 1 : m 1 m 2 ; z 0.76;P-value 0.4472; do not reject the null hypothesis.IS–47