An Internet service provider is interested in testing to see if there is a difference in the mean weekly connect time for users who come into the service through a dial-up line,DSL,or cable Internet.To test this,the ISP has selected random samples from each category of user and recorded the connect time during a week period.The following data were collected: Assuming that the test is to be conducted at a 0.01 level of significance,what would the critical value be for this test?
A)F = 1.93
B)F = 3.555
C)t = 2.8784
D)F = 6.013

Question

An Internet service provider is interested in testing to see if there is a difference in the mean weekly connect time for users who come into the service through a dial-up line,DSL,or cable Internet.To test this,the ISP has selected random samples from each category of user and recorded the connect time during a week period.The following data were collected:  Assuming that the test is to be conducted at a 0.01 level of significance,what would the critical value be for this test?
A)F = 1.93 
B)F = 3.555 
C)t = 2.8784 
D)F = 6.013

Quizplus · Accepted Answer

Since we are testing for a difference in means between more than two groups, we need to use an ANOVA test. The critical value for ANOVA is given by the F-distribution.

To find the critical value, we need to calculate the degrees of freedom for the numerator and denominator.

There are three groups, so the numerator degrees of freedom is 3-1 = 2.

The total sample size is 30 (10 in each group), so the denominator degrees of freedom is 30-3 = 27.

Using a table or calculator, we find that the critical value of F for a 0.01 level of significance and 2 and 27 degrees of freedom is 6.013.

Therefore, the answer is D.

An Internet Service Provider Is Interested in Testing to See