Exam 14: Analysis of Categorical Data

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: An airline is considering changing the color scheme of its planes' interiors.A focus group of 220 people was asked which color scheme they preferred.Of those who expressed a preference,87 preferred the new color scheme,while 121 preferred the old. -A recent survey examined the first-year salaries of 178 MBA graduates.The kurtosis for this data set was calculated to be 3.56,with a skewness of 0.29.Is there sufficient evidence to reject the null hypothesis that first-year salaries for MBA graduates are normally distributed?

A chi-square test for independence with 8 degrees of freedom results in a test statistic of 18.21.Using the chi-square table,the most accurate statement that can be made about the p-value for this test is that:

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: A random sample of 16 male students and an independent random sample of 16 female students were asked to write essays at the conclusion of a writing course.These essays were then ranked from 1(best)to 30(worst)by a professor.The following rankings resulted. -Test the null hypothesis that in the aggregate the two genders are equally ranked against a two-sided alternative.

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: A brand manager is interested in determining if consumers prefer the new fragrance associated with a detergent.She surveyed 212 consumers and has them rank the new and old fragrances on a scale of 1 to 10.Of the 198 consumers who scored a different score on the new fragrance than on the old,the absolute values of the differences in their ratings were ranked.The smaller of the ranked sums,8,208,was for those individuals who rated the original fragrance higher. -In a recent survey,23 customers were asked whether they preferred Coca-Cola or Pepsi.Of those respondents who had a preference,6 preferred Coca-Cola while 13 preferred Pepsi.Is there sufficient evidence that people prefer Pepsi to Coca-Cola?

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: The following table provides the test scores for the first two exams in a statistics course. Student -Test whether the students did better on the second exam than the first.

Consider a cell in a contingency table.Given the cell's row total of 40,the cell's column total of 50,and a sample size of 250,the cell's expected frequency:

Which of the following will never be a required condition of a nonparametric test?

A two-way table used for a test of independence is sometimes called a:

The normal approximation to the sign test is acceptable if the sample size exceeds 15.

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: A statistics professor is interested in seeing if his students performed better on the second exam than the first.For the 45 students who scored a different score on the second exam than the first,the absolute values of the differences in their scores were ranked.The smaller of the ranked sums,320,was for those individuals who scored lower on their second exam. -Which nonparametric method is appropriate for analyzing these results?

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: A random sample of 16 male students and an independent random sample of 16 female students were asked to write essays at the conclusion of a writing course.These essays were then ranked from 1(best)to 30(worst)by a professor.The following rankings resulted. -In a period of 50 minutes there were a total of 90 arrivals at a highway toll booth.The accompanying table shows the frequency of arrivals per minute over this period.Test at the 5% level the null hypothesis that the population distribution is Poisson.

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: The following table provides the test scores for the first two exams in a statistics course. Student -Which nonparametric method is appropriate for analyzing these data?

A marketing researcher asked a sample of 120 consumers regarding their preferred packaging for a new product.They had four different package styles to choose from.Of the 120 people,39 preferred Package A,27 preferred Package B,24 preferred Package C,and the rest preferred Package D.Is there evidence to suggest that the preferences are evenly spread among the four packages?

The decision rule in a chi-square goodness-of-fit-test is to reject the null hypothesis if the computed chi-square test statistic is:

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: Students in a statistics course were given a written examination as well as a project to complete as part of their final grade.For a random sample of 10 students,the scores on both the exam and the project are given below. -Calculate the spearman rank correlation coefficient using statistical software.

A chi-square test for independence with 8 degrees of freedom results in a test statistic of 23.158.Using the chi-square table,the most accurate statement that can be made about the p-value for this test is that p-value > 0.005.

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION: A large department store records the number of returns per day in women's dresses for reasons such as wrong size;husband didn't like it,color,etc.The manager of the women's dresses department recalls from her statistics class in college that the Poisson distribution might describe such events.A random sample of 150 days is taken.The number of returns per day in the sample as well as the observed frequencies is shown in the table below: She tests the hypothesis that returns per day are Poisson distributed with a population mean equal to 1.90.Her significance level is 0.05 -A random sample of 75 medical students was asked to estimate how much money they spent on textbooks in a year.The sample skewness of these amounts was found to be 0.90 and sample kurtosis was 4.0.Test at the 5% level the null hypothesis that the population distribution of amounts spent is normal.

A chi-square test for independence is applied to a contingency table with 3 rows and 4 columns for two qualitative variables.The degrees of freedom for this test must be 12.

Which of the following statements about nonparametric tests is false?

The Wilcoxon rank sum test is used to compare two populations when the samples are independent and the data are either ordinal or interval but not normally distributed.