A veterinarian notes the age (months) at which dogs are brought in to the clinic to be neutered. $\begin{array}{|c|c|c|c|}
\hline&\text {Collies }&\text { Terriers}&\text { Chows }\
\hline\text { Male }& 10 & 14 & 8 \
&9 & 10 & 18 \
&12 & 8 & 11 \
\hline \text { Female }&15 & 17 & 9 \
&7 & 11 & 15 \
&8 & 6 & 8 \
\hline
\end{array}$ Numerator degrees of freedom for the ANOVA interaction test would be:
A)2.
B)3.
C)6.
D)can't tell.

Question

Quizplus · Accepted Answer

The numerator degrees of freedom for the interaction in a two-way ANOVA is calculated as (number of levels of factor A - 1) * (number of levels of factor B - 1). Here, there are 2 levels for gender (male, female) and 3 levels for breed (Collies, Terriers, Chows), so (2-1)*(3-1) = 2.

A Veterinarian Notes the Age (Months) at Which Dogs Are