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Unformatted text preview: Solutions to Chapter 11 Problems 11.2 (a) Observed Freq Expected Freq Observed Freq Expected Freq Total Obs, Row 1 20 25 30 25 50 chisq contrib= 1.00 chisq contrib= 1.00 Observed Freq Expected Freq Observed Freq Expected Freq Total Obs, Row 2 30 25 20 25 50 chisq contrib= 1.00 chisq contrib= 1.00 Total Obs, Col 1 Total Obs, Col 2 GRAND TOTAL 50 50 100 (b) Decision rule: If 2 χ > 3.841, reject H . Test statistic: χ 2 = ∑ ( f – f e ) 2 f e = 1.00 + 1.00 + 1.00 + 1.00 = 4.00 Decision: Since χ 2 calc = 4.00 is above the critical value of 3.841, reject H . 11.8 (a) H : p 1 = p 2 H 1 : p 1 ≠ p 2 Decision rule: df = 1. If χ 2 > 3.841, reject H . Test statistic: χ 2 = 33.3333 Decision: Since χ 2 calc = 33.3333 is above the upper critical bound of 3.841, reject H . There is enough evidence to conclude that there is a significant difference between the proportion of males and females who place more importance on brand names today than a few years ago. (b) p value is virtually 0. The probability of obtaining a test statistic as large as 33.3333 or larger when the null hypothesis is true is virtually 0. 11.12 (a) PHStat output: ChiSquare Test Observed Frequencies Drug Regimen Result A B C D Total Severe 714 785 754 820 3073 Not Severe 9630 9543 9042 9557 37772 Total 10344 10328 9796 10377 40845 Expected Frequencies Drug Regimen Result A B C D Total Severe 778.2375 777.0338 737.0084 780.7203 3073 Not Severe 9565.762 9550.966 9058.992 9596.28 37772 Total 10344 10328 9796 10377 40845 Data Level of Significance 0.05 Number of Rows...
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 Spring '08
 Judd
 Statistical hypothesis testing, Freq Expected Freq

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