Exam 11: Analysis of Variance

Two accounting professors decided to compare the variation of their grading procedures. To accomplish this they each graded the same 10 exams with the following results: What is the critical value of F at the 0.01 level of significance?

i. The statistical technique used to test the equality of three or more population means is called analysis of variance (ANOVA) ii. To employ ANOVA, the populations should have approximately equal standard deviations. iii. To employ ANOVA, the populations being studied must be approximately normally distributed.

i. For the population means, the alternate hypothesis used in the analysis of variance test states that µ1 = µ2 = µ3. Ii) For an ANOVA test, rejection of the null hypothesis does not identify which populations differ Significantly. Iii) The null hypothesis for an ANOVA is µ1 - µ2 = µ3

i. To employ ANOVA, the populations being studied must be approximately normally distributed. ii. A technique that is efficient when simultaneously comparing more than two population means is known as analysis of variance (ANOVA) iii. The least number of sources of variation in ANOVA is two.

i. The statistical technique used to test the equality of three or more population means is called analysis of variance (ANOVA) ii. To employ ANOVA, the populations need not have equal standard deviations. iii. To employ ANOVA, the populations being studied must be approximately normally distributed.

A large department store examined a sample of the 18 credit card sales and recorded the amounts charged for each of three types of credit cards: MasterCard, Visa and American Express. Six MasterCard sales, seven Visa and five American Express sales were recorded. The store used ANOVA to test if the mean sales for each credit card were equal. What are the degrees of freedom for the F statistic?

Which of the following are characteristics of the F distribution?

i. The shape of the F distribution is determined by the degrees of freedom for the F-statistic, one for the numerator and one for the denominator. ii. The F distribution's curve is positively skewed. Iii) Unlike Student's t distribution, there is only one F distribution.

A manufacturer of automobile transmissions uses three different processes. The management ordered a study of the production costs to see if there is a difference among the three processes. A summary of the findings is shown below. What is the calculated F?

Several employees have submitted different methods of assembling a product. Sample data for each method are: How many treatments are there?

A preliminary study of hourly wages paid to unskilled employees in three metropolitan areas was conducted. Seven employees were included from Area A, 9 from Area B and 12 from Area C The test statistic was computed to be 4.91. What can we conclude at the 0.05 level?

In a study of low tar cigarettes, five cigarettes from each of three brands were tested to see if the mean amount of tar per cigarette differs among the brands. i. There are 2 degrees of freedom for the numerator. Ii) There are 12 degrees of freedom for the denominator. Iii) If the sum of squares for the brands is 0.07, the mean square for brands is 0.035.

An electronics company wants to compare the quality of their cell phones to the cell phones from three competitors. They sample 10 phones from each company and count the number of defects for each phone. If ANOVA is used to compare the average number of defects, the treatments would be defined as:

In an effort to determine the most effective way to teach safety principles to a group of employees, four different methods were tried. Some employees were given programmed instruction booklets and worked through the course at their own pace. Other employees attended lectures. A third group watched a television presentation, and a fourth group was divided into small discussion groups. A high of 10 was possible. Samples of five tests were selected from each group. The test grade results were: Using Excel to assist in determining if all methods generate the same results, what test would be used?

A manufacturer of automobile transmissions uses three different processes. The management ordered a study of the production costs to see if there is a difference among the three processes. A summary of the findings is shown below. What is the critical value of F at the 5% level of significance?

If an ANOVA test is conducted and the null hypothesis is rejected, what does this indicate?

Two accounting professors decided to compare the variation of their grading procedures. To accomplish this they each graded the same 10 exams with the following results: What are the degrees of freedom for the numerator of the F ratio?

Which one of the following is not assumed in the use of ANOVA?

A manufacturer of automobile transmissions uses three different processes. The management ordered a study of the production costs to see if there is a difference among the three processes. A summary of the findings is shown below. What is the mean square for treatments?

In a study of low tar cigarettes, five cigarettes from each of three brands were tested to see if the mean amount of tar per cigarette differs among the brands. i. There are 2 degrees of freedom for the numerator. ii. There are 14 degrees of freedom for the denominator. iii. If the sum of squares for the brands is 0.07, the mean square for brands is 0.035.