A major consumer group recently undertook a study to determine whether automobile customers would rate the quality of cars differently whether they were manufactured in the U.S. ,Europe,or Japan.To conduct this test,a sample of 20 individuals was asked to look at mid-range model cars made in each of the three countries.The individuals in the sample were then asked to provide a rating for each car on a scale of 1 to 1000.The following computer output resulted,and the tests were conducted using a significance level equal to 0.05. ANOVA: Two-Factor Without Replication Based upon the data,which of the following statements is true?
A)Blocking was effective.
B)Blocking was not effective.
C)The primary null hypothesis should not be rejected.
D)The averages for the 20 people are not all the same.

Question

A major consumer group recently undertook a study to determine whether automobile customers would rate the quality of cars differently whether they were manufactured in the U.S. ,Europe,or Japan.To conduct this test,a sample of 20 individuals was asked to look at mid-range model cars made in each of the three countries.The individuals in the sample were then asked to provide a rating for each car on a scale of 1 to 1000.The following computer output resulted,and the tests were conducted using a significance level equal to 0.05. ANOVA: Two-Factor Without Replication   Based upon the data,which of the following statements is true?
A)Blocking was effective. 
B)Blocking was not effective. 
C)The primary null hypothesis should not be rejected. 
D)The averages for the 20 people are not all the same.

Quizplus · Accepted Answer

The output shows that the p-value for the interaction effect is less than 0.05, which means that the blocking was not effective. This is because the interaction effect measures whether the effect of one factor on the response variable changes depending on the level of the other factor. Since the p-value is less than 0.05, we can conclude that the effect of the country of origin on the ratings of the cars varies depending on the individual providing the rating. Therefore, the blocking technique used in this study was not effective. The other statements cannot be concluded based on the given information.

A Major Consumer Group Recently Undertook a Study to Determine