Does the Environment Affect Bird Weight? Researchers Measured the Weight

Multiple Choice

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.
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$$\begin{array}{l}\begin{array} { l r r r } \text { Factor } & \text { Type } & \text { Levels } & \text { Values } \\\text { malefemale } & \text { fixed } & 2 & f , m \\\text { origin } & \text { fixed } & 2 & \text { aviary, wild }\end{array}\\\\\text { Analysis of Variance for bird weight }\\\\\begin{array} { l r r r r r } \text { Source } & \text { DF } & \text { SS } & \text { MS } & \text { F } & \text { P } \\\text { Malefemale } & 1 & 10.844 & 10.844 & & \\\text { origin } & 1 & 19.607 & 19.607 & & \\\text { interaction } & 1 & 0.340 & 0.340 & & \\\text { Error } & 48 & 125.140 & 2.607 & &\end{array}\end{array}$$ 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?

A) Nonsignificant interaction effect: therefore, we can discuss the main effects separately.
B) Nonsignificant interaction effect; therefore, sex and origin do not influence mean weight in finches.
C) Significant interaction effect; therefore, we can discuss the main effects separately.
D) Significant interaction effect; therefore, we should discuss the main effects together.