Exam 16: Analysis of Variance

Use the following information for questions: Fifty-five customers of a large-chain grocery store are asked to fill out an in-store survey. One of the questions on the survey asks about the use of coupons, while another question asks how much money the customer spent on groceries during that specific trip. Mood's median test is used to compare the median amounts spent in the store for four groups defined by the type of coupons the customers used. The categories were 'no coupons', 'coupons from the newspaper', coupons from the store's weekly flyer', and 'both types of coupons'. The SPSS output is provided below. -What is the null hypothesis for this test?

Use the following information for questions: A company that owns five resort hotels wants to compare guest satisfaction across the hotels. For each hotel, the company's research department randomly sampled 21 people who had stayed at the hotel during the past month and asked them to rate their expectation of the hotel before their stay and to rate the quality of their actual stay at the hotel. Both observations used a rating scale of 0 to 10 with 0 = "very poor" and 10 = "excellent". For each guest, the researchers calculated a performance gap score, defined as the difference between a guest's prior expectation rating and actual quality rating. -What are the degrees of freedom of the F-distribution if we were to use an ANOVA to compare the population means?

Use the following information for questions: A study compared testosterone levels among athletes in four sports: soccer, track, Lacrosse, and water polo. The total sample size was n =30 (10 soccer, 10 track, 5 Lacrosse, and 5 water polo). A one-way analysis of variance was used to compare the population mean levels for the four sports. -What are the numerator and denominator degrees of freedom for the F-test?

Use the following information for questions: A study compared grade point averages (GPA) for students in a class: students were divided by 6 locations where they usually sat during lecture (i.e. left or right front, left or right center, left or right rear). A total sample size of 12 students was studied (2 students from each section) using one-way analysis of variance. -What are the numerator and denominator degrees of freedom for the F-test?

Use the following information for questions: Using data from 496 respondents in a past General Social Survey, a Kruskal-Wallis test is done to compare the median ages in five populations defined by the highest educational degree received (no high school degree, high school degree, junior college, bachelor degree, graduate degree). The Minitab output is provided below. -At a significance level of 0.05, what is the conclusion?

Use the following information for questions: A study was conducted to compare the mean sulfur dioxide concentrations for three cities. Independent random samples were obtained from each city and the concentration levels along with some summaries are provided below: -Multiple comparisons output using Tukey's procedure is provided. Does there seem to be a difference between the average sulfur dioxide concentrations for City 1 versus City 2 at the 10% level? Explain your answer (include relevant numbers from the output)..

Use the following information for questions: A supervisor wants to study the relationship between employee training and time required to complete a job-related task. Three levels of employee training are considered: Beginner, Intermediate, and Advanced. Thirty new employees were randomly selected and each employee was randomly assigned to one of the three training levels. After the training was complete, the time (in minutes) it takes each employee to complete the task is recorded. Descriptive statistics and ANOVA results are given below. -Multiple comparisons were performed using Tukey's procedure. The resulting table is given below Clearly select all pairs that are significantly different at the 5% level.

Use the following information for questions: A researcher is hired by a company that sells appliances to investigate whether there is any difference in the average ratings that customers give to a DVD player between three different age groups. Sixty-eight people were asked to fill out a questionnaire and rate the DVD player by answering various questions (easy to use? looks nice? manual understandable?) after using it for a week. The scores (a value between 1 and 50) were recorded and a one-way ANOVA was performed. Partial SPSS output is provided below. -What is the numerical value of the test statistic that we would calculate to assess equality of the average DVD assessment scores for the three different age groups? Include the symbol we use to represent this test statistic in your answer.

Use the following information for questions: A study compared weight loss among 5 different diet programs. A total sample size of 25 people was studied (5 people from each program) using one-way analysis of variance. -The sum of squares for groups is SS Groups = 80. What is the Mean Square for groups (MS Groups)?

Use the following information for questions: Five different training programs for improving endurance are compared. Forty individuals are randomly divided into five groups of n = 8 each and a different training program is assigned to each group. After two months, the improvement in endurance is recorded for each participant. -A one-way analysis of variance is used to compare the five training programs, and the resulting p-value is 0.023. At a significance level of 0.05, the appropriate conclusion about mean improvement in endurance is that it

Use the following information for questions: A study compared grade point averages (GPA) for students in a class: students were divided by 6 locations where they usually sat during lecture (i.e. left or right front, left or right center, left or right rear). A total sample size of 12 students was studied (2 students from each section) using one-way analysis of variance. -The p-value for the F-test is 0.46. If the significance level = 0.05, what is the conclusion?