Does the environment affect bird weight? Researchers measured the weight (in grams) of male and female adult finches that were either raised in an aviary or caught in the wild. This observational study does not have a balanced design, particularly because finches caught in the wild were more difficult to obtain. A total of 52 finches were studied. A partial ANOVA table is provided below, along with an interaction plot displaying the group means.

$$\begin{array}{l}
\begin{array} { l r r r }
\text { Factor } & \text { Type } & \text { Levels } & \text { Values } \
\text { malefemale } & \text { fixed } & 2 & f , m \
\text { origin } & \text { fixed } & 2 & \text { aviary, wild }
\end{array}\
\
\text { Analysis of Variance for bird weight }\
\
\begin{array} { l r r r r r }
\text { Source } & \text { DF } & \text { SS } & \text { MS } & \text { F } & \text { P } \
\text { Malefemale } & 1 & 10.844 & 10.844 & & \
\text { origin } & 1 & 19.607 & 19.607 & & \
\text { interaction } & 1 & 0.340 & 0.340 & & \
\text { Error } & 48 & 125.140 & 2.607 & &
\end{array}
\end{array}$$ S = 1.61465 R-Sq = 23.88% R-Sq(adj) = 19.12%
The first step in analysis is to analyze the interaction effect. Using a significance level of 0.05, what do the results suggest about the interaction effect?

Question

Does the environment affect bird weight? Researchers measured the weight (in grams) of male and female adult finches that were either raised in an aviary or caught in the wild. This observational study does not have a balanced design, particularly because finches caught in the wild were more difficult to obtain. A total of 52 finches were studied. A partial ANOVA table is provided below, along with an interaction plot displaying the group means.
​
$$\begin{array}{l}
\begin{array} { l r r r } 
\text { Factor } & \text { Type } & \text { Levels } & \text { Values } \
\text { malefemale } & \text { fixed } & 2 & f , m \
\text { origin } & \text { fixed } & 2 & \text { aviary, wild }
\end{array}\
\
\text { Analysis of Variance for bird weight }\
\
\begin{array} { l r r r r r } 
\text { Source } & \text { DF } & \text { SS } & \text { MS } & \text { F } & \text { P } \
\text { Malefemale } & 1 & 10.844 & 10.844 & & \
\text { origin } & 1 & 19.607 & 19.607 & & \
\text { interaction } & 1 & 0.340 & 0.340 & & \
\text { Error } & 48 & 125.140 & 2.607 & &
\end{array}
\end{array}$$ S = 1.61465 R-Sq = 23.88% R-Sq(adj) = 19.12%
 The first step in analysis is to analyze the interaction effect. Using a significance level of 0.05, what do the results suggest about the interaction effect?

Quizplus · Accepted Answer

The p-value for the interaction effect is not provided, but we are told that it is not significant at the 0.05 level. Therefore, we can discuss the main effects separately without considering the interaction.

Does the Environment Affect Bird Weight? Researchers Measured the Weight