Exam 11: Two Sample Tests of Hypothesis

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 are the degrees of freedom for the denominator?

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?

i. One characteristic of the F distribution is that computed F can only range between -1 and +1. ii. 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. iii. The F distribution's curve is positively skewed.

An ANOVA showed the following comparison of four treatment means. Which treatment means are significantly different?

A random sample of 30 executives from companies with assets over $1 million was selected and Asked for their annual income and level of education. The ANOVA comparing the average income Among three levels of education rejected the null hypothesis. The Mean Square Error (MSE) was 243)7. The following table summarized the results: When comparing the mean annual incomes for executives with Undergraduate and Master's Degree or more, the following 95% confidence interval can be constructed:

Using the MegaStat printout below to compare the mean annual incomes for executives with Undergraduate and High School or less, the following statements can be made:

i. The F distribution is positively skewed and its values may range from 0 to plus infinity. ii. The F distribution's curve is positively skewed. iii. Like Student's t distribution, a change in the degrees of freedom causes a change in the shape of The F distribution.

If the confidence interval for the difference in treatment means contains zero, then:

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.

A random sample of 30 executives from companies with assets over $1 million was selected and Asked for their annual income and level of education. The ANOVA comparing the average income Among three levels of education rejected the null hypothesis. The Mean Square Error (MSE) was 243)7. The following table summarized the results: When comparing the mean annual incomes for executives with a High School education or less and Undergraduate Degree, the 95% confidence interval shows an interval of 11.7 to 42.7 for the Difference. This result indicates that:

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 H1?

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 are the degrees of freedom for the numerator of the F ratio?

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?

i. If the computed value of F is 4.01 and the critical value is 2.67, we would conclude that all the Population means are equal. ii. Rejecting the null hypothesis in ANOVA indicates that the population means are equal. iii. The null hypothesis for an ANOVA is μ1 - μ2 ≠ μ3.

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 are the total degrees of freedom?

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: At the 0.01 level, what is the critical value?

Suppose a package delivery company purchased 14 trucks at the same time. Five trucks were Purchased from manufacturer A, four from B and five from manufacturer C The cost of maintaining each truck was recorded. The company used ANOVA to test if the mean maintenance cost for Trucks from each manufacturer were equal. To apply the F test, how many degrees of freedom are In the denominator?

The annual dividend rates for a random sample of 16 companies in three different industries, Utilities, banking, and insurance were recorded. The ANOVA comparing the mean annual dividend Rate among three industries rejected the null hypothesis that the dividend rates were equal. The Mean Square Error (MSE) was 3.36. The following table summarized the results: Based on the comparison between the mean annual dividend rate for companies in utilities and Banking, the 95% confidence interval shows an interval of 1.28 to 6.28 for the difference. This result Indicates that _____________________.

A random sample of 30 executives from companies with assets over $1 million was selected and Asked for their annual income and level of education. The following table summarized the results: Using this output, what conclusions can you draw?

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?