The Internal Revenue Service wishes to study the time required to process tax returns in three regional centers.A random sample of three tax returns is chosen from each of three centers.The time (in days)required to process each return is recorded as shown below. Degrees of freedom for the between-groups sum of squares in the ANOVA would be:
A) 11.
B) 2.
C) 4.

Question

The Internal Revenue Service wishes to study the time required to process tax returns in three regional centers.A random sample of three tax returns is chosen from each of three centers.The time (in days)required to process each return is recorded as shown below.  Degrees of freedom for the between-groups sum of squares in the ANOVA would be:
A) 11. 
B) 2. 
C) 4.

Quizplus · Accepted Answer

The between-groups sum of squares has two degrees of freedom, which correspond to the number of groups minus one. In this case, there are three centers, so the degrees of freedom for the between-groups sum of squares is 3-1=2. The within-groups sum of squares will have 9 degrees of freedom (3 samples per center, minus 1 for each sample mean calculated).

The Internal Revenue Service Wishes to Study the Time Required