Select the letter of the most correct response for

Direction: Select the letter of the most correct response for multiple choice problems. Show workfor problems 12, 13 and 14. Problems 12, 13 and 141. The t test for the difference between the means of 2 independent populations assumes that therespectivea) sample sizes are equal.b) sample variances are equal.c) populations are approximately normal.d) All of the above.ANSWER:TYPE: MC DIFFICULTY: ModerateKEYWORDS: pooled variance, t test, assumption2. The t test for the mean difference between 2 related populations assumes that thea) population sizes are equal.b) sample variances are equal.c) population of differences is approximately normal or sample sizes are large enough.d) All of the above.ANSWER:TYPE: MC DIFFICULTY: ModerateKEYWORDS: t test, mean difference, assumption3. If we are testing for the difference between the means of 2 related populations with samples of n1= 20 and n2 = 20, the number of degrees of freedom is equal toa) 39.b) 38.c) 19.d) 18.ANSWER:TYPE: MC DIFFICULTY: EasyKEYWORDS: t test, mean difference, degrees of freedom4. In testing for differences between the means of two related populations, the null hypothesis isa).H0 : D 2b)H0 : D 0.1c)d)H0 : D 0H0 : D 0..ANSWER:TYPE: MC DIFFICULTY: EasyKEYWORDS: t test, mean difference, form of hypothesis5. In testing for differences between the means of two independent populations, the null hypothesisis:a)= 2.H 0 : 1 2b)c)d)H0 : 1 – 2H0 : 1 – 2H0 : 1 – 2= 0.> 0.< 2.ANSWER:TYPE: MC DIFFICULTY: EasyKEYWORDS: pooled variance, t test, form of hypothesis6. When testing for the difference between 2 population variances with sample sizes of n1 = 8 and n2= 10, the number of degrees of freedom area) 8 and 10.b) 7 and 9.c) 18.d) 16.ANSWER:TYPE: MC DIFFICULTY: EasyKEYWORDS: F test, difference between two variances, degrees of freedom7. The statistical distribution used for testing the difference between two population variances is the___ distribution.a) tb) standardized normalc) binomiald) FANSWER:2TYPE: MC DIFFICULTY: EasyKEYWORDS: F test, difference between two variances, degrees of freedom8. The test for the equality of two population variances is based ona) the difference between the 2 sample variances.b) the ratio of the 2 sample variances.c) the difference between the 2 population variances.d) the difference between the sample variances divided by the difference between thesample means.ANSWER:TYPE: MC DIFFICULTY: EasyKEYWORDS: F test, difference between two variancesTABLE 10-2A researcher randomly sampled 30 graduates of an MBA program and recorded data concerning theirstarting salaries. Of primary interest to the researcher was the effect of gender on starting salaries.Analysis of the mean salaries of the females and males in the sample is given below.Hypothesized DifferenceLevel of SignificancePopulation 1 SampleSample SizeSample MeanSample Standard DeviationPopulation 2 SampleSample SizeSample MeanSample Standard DeviationDifference in Sample Meanst-Test StatisticLower-Tail TestLower Critical Valuep-Value00.051848266.713577.63125500011741.29-6733.3-1.40193-1.701130.0859629. Referring to Table 10-2, the researcher was attempting to show statistically that the female MBAgraduates have a significantly lower mean starting salary than the male MBA graduates.According to the test run, which of the following is an appropriate alternative hypothesis?a)H1 : females malesb)c)H1 : females malesH1 : females males3d)H1 : females malesANSWER:TYPE: MC DIFFICULTY: ModerateKEYWORDS: pooled variance, t test, form of hypothesis10. Referring to Table 10-2, the researcher was attempting to show statistically that the female MBAgraduates have a significantly lower mean starting salary than the male MBA graduates. From theanalysis in Table 10-2, the correct test statistic is:a) 0.0860b) – 1.4019c) – 1.7011d) – 6,733.33ANSWER:TYPE: MC DIFFICULTY: ModerateKEYWORDS: pooled variance, t test, test statistic11. Referring to Table 10-2, the researcher was attempting to show statistically that the female MBAgraduates have a significantly lower mean starting salary than the male MBA graduates. Theproper conclusion for this test is:a) At the= 0.10 level, there is sufficient evidence to indicate a difference in the meanstarting salaries of male and female MBA graduates.b) At the= 0.10 level, there is sufficient evidence to indicate that females have a lowermean starting salary than male MBA graduates.c) At the= 0.10 level, there is sufficient evidence to indicate that females have a highermean starting salary than male MBA graduates.d) At the= 0.10 level, there is insufficient evidence to indicate any difference in themean starting salaries of male and female MBA graduates.ANSWER:TYPE: MC DIFFICULTY: ModerateKEYWORDS: pooled variance, t test, conclusion12. Referring to Table 10-2, what is the 95% confidence interval estimate for the difference betweentwo means?4ANSWER:TYPE: PR DIFFICULTY: ModerateKEYWORDS: confidence interval, difference between the mean13. Treat the following samples as independent and prove whether or not the based on these samplesthe populations that samples are taken from have equal means. Assume populations have equal5variances. Show six step hypothesis testing in blank space provided below. You can use computerto calculate mean and standard deviation of each sample.Untreated163.368158.018153.871164.096155.184155.496160.920165.917169.091175.276177.135164.903167.802160.818167.433164.538164.525171.230175.964166.311Treated158.239138.216168.006149.654145.456168.178154.321162.763161.020167.706150.226155.620151.233158.653151.204150.869161.657157.016156.670147.9206TABLE 10-514. To test the effectiveness of a business school preparation course, 8 students took a generalbusiness test before and after the course. The results are given below:Exam ScoreStudent Before Course (1)15302690391047005450682078208630Exam ScoreAfter Course (2)6707701,000710550870770610Show 6 steps hypothesis testing and prove scores after are statistically higher than before course istaken.715. Referring to Table 10-5, the number of degrees of freedom isa) 14.b) 13.c) 8.d) 7.ANSWER:TYPE: MC DIFFICULTY: EasyKEYWORDS: t test, mean difference, degrees of freedom16. Referring to Table 10-5, the value of the sample mean difference is _______ if the differencescores reflect the results of the exam after the course minus the results of the exam before thecourse.a) 0b) 50c) 68d) 400ANSWER:TYPE: MC DIFFICULTY: EasyKEYWORDS: t test, mean difference, test statistic17. Referring to Table 10-5, the value of the standard error of the difference scores isa) 65.027b) 60.828c) 22.991d) 14.696ANSWER:TYPE: MC DIFFICULTY: EasyKEYWORDS: t test, mean difference, standard error18. Referring to Table 10-5, what is the critical value for testing at the 5% level of significancewhether the business school preparation course is effective in improving exam scores?a) 2.365b) 2.145c) 1.761d) 1.895ANSWER:TYPE: MC DIFFICULTY: EasyKEYWORDS: t test, mean difference, critical value19. Referring to Table 10-5, at the 0.05 level of significance, the conclusion for this hypothesis testwould be:a) the business school preparation course does improve exam score.b) the business school preparation course does not improve exam score.c) the business school preparation course has no impact on exam score.d) It cannot be drawn from the information given.ANSWER:TYPE: MC DIFFICULTY: Easy8KEYWORDS: t test, mean difference, conclusion9