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 those with an undergraduate degree, the 95% confidence interval shows an interval of 11.7 to 42.7 for the difference. This result indicates that __________________.
A) there is no significant difference between the two incomes
B) the interval contains a difference of zero
C) executives with an undergraduate degree earn significantly more than executives with a high school education or less
D) executives with an undergraduate degree earn significantly less than executives with a high school education or less

Question

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 those with an undergraduate degree, the 95% confidence interval shows an interval of 11.7 to 42.7 for the difference. This result indicates that __________________.
A) there is no significant difference between the two incomes 
B) the interval contains a difference of zero 
C) executives with an undergraduate degree earn significantly more than executives with a high school education or less 
D) executives with an undergraduate degree earn significantly less than executives with a high school education or less

Quizplus · Accepted Answer

The 95% confidence interval shows that the difference in mean annual incomes for executives with a high school education or less and those with an undergraduate degree is between 11.7 and 42.7, which does not include zero. Therefore, we can conclude that executives with an undergraduate degree earn significantly more than executives with a high school education or less.

A Random Sample of 30 Executives from Companies with Assets