Exam 12: Analysis of Variance

A company compared the variance of salaries for employees who have been employed for 5 years or less with employees who have been employed for 10 years or more. They randomly selected 21 employees with 5 years or less experience and 15 employees with 10 years or more experience. The standard deviation for the group with 5 years or less experience was $2,225; the standard deviation for the group with 10 years or more experience was $1,875. Using the 0.05 significance level, what is the decision regarding the null hypothesis?

The college of business was interested in comparing the attendance for three different class times for a business statistics class. The data follow. What is the treatment variable?

In a one-way ANOVA, ______ degrees of freedom are associated with the numerator of the F ratio.

The alternative hypothesis used in ANOVA is H₁: All population means are equal.

The college of business was interested in comparing the attendance for three different class times for a business statistics class. The data follow. What is the critical F statistic for testing the hypothesis of equal treatment means at the 0.05 significance level?

In a two-way ANOVA with interaction, a significant interaction term indicates that _________________.

Suppose an automobile manufacturer designed a radically new lightweight engine and wants to recommend the grade of gasoline that will have the best fuel economy. The four grades are regular, economy, premium, and super premium. The test car made three trial runs on the test track using each of the four grades. The miles per gallon were recorded for each grade. At the 0.05 level, what is the critical value of F used to test the hypothesis that the miles per gallon for each fuel are the same?

If there are 5 levels of Factor A and 7 levels of Factor B for an ANOVA with interaction, what are the interaction degrees of freedom?

Which statement is correct about the F distribution?

An ANOVA comparing the waiting times for four different emergency rooms shows the following comparison of the four mean waiting times. Which two pairs of means are significantly different?

For the hypothesis test, with n₁ = 10 and n₂ = 10, the F-test statistic is 2.56. At the 0.01 level of significance, we would reject the null hypothesis.

A random sample of 20 female 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 250. The following table summarized the results: To compare the mean annual incomes of female executives with a high school education or less and female executives with a master's degree or more, compute the 90% confidence interval.

In ANOVA, the null hypothesis is:

Two accounting professors decided to compare the variance of their grading procedures. To accomplish this, they each graded the same 10 exams, with the following results: What is the null hypothesis?