To test whether students in a higher grade level will be less disruptive in class, a school psychologist records the number of documented interruptions during one day of classes from nine local high schools. The sample consisted of nine(n= 9)

freshman, sophomore, junior, and senior high school classes. The data for each high school class are given in the table.

High School Class:

Freshman 0 6 2 3 2 1 1 4 5

Sophomore 6 3 4 0 4 1 2 2 0

Junior 6 0 4 3 3 5 5 0 6

Senior 4 4 1 2 3 3 2 4 2

(a) Complete theF-table. (Round your answers to two decimal places.)

Source of Variation : SS df MS F

Between groups ______ ___ ____ ____

Within groups (error)________ _____ ___ ___

Total ss_____ df ____

(b) Is it necessary to compute a post hoc test? Explain. (Assume alpha equal to 0.05.)

Yes, post hoc analyses are appropriate because the ANOVA is significant?

No, post hoc analyses are not appropriate because the ANOVA is not significant?