Researchers Investigated the Effects of Acute Stress on Emotional Picture

Researchers investigated the effects of acute stress on emotional picture processing and recall by randomly assigning 40 adult males to receive either a stressful cold stimulus or a neutral warm stimulus before viewing pictures. The researchers computed the relative brainwave amplitude (in microvolts, μV) for each subject viewing unpleasant versus neutral pictures. They also recorded how many pictures the subjects were able to recall 24 hours later. The data are displayed in the following scatterplot.
The following model is proposed for predicting the brainwave relative amplitude ("amplitude") from the number of images recalled ("recall") , the indicator variable reflecting the nature of the stimulus ("stress") , and an interaction term ("recall*stress") :
Amplitude_i = β₀ + β₁ (recall_i) + β₂ (stress_i) + β₃ (recall*stress_i) + ε_i
Where the deviations ε_i are assumed to be independent and Normally distributed with mean 0 and standard deviation σ. This model was fit to the sample of 40 adult males. The following results summarize the least-squares regression fit of this model:
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$\begin{array}{lrr}\text { Predictor } & \text { Coef } & \text { SE Coef } \\\text { Constant } & 4.795 & 1.329 \\\text { recall } & -0.1139 & 0.1069 \\\text { stress } & -4.262 & 2.205 \\\text { recall }{ }^{*} \text { stress } & 0.4337 & 0.1677 \\\mathrm{~S}=2.13946 & \text { R-Sq }=22.8 \% &\end{array}$

$\begin{array}{l}\text { Analysis of Variance }\\\begin{array}{lrrr}\text { Source } & \text { DF } & \text { SS } & \text { MS } \\\text { Regression } & 3 & 48.788 & 16.263 \\\text { Residual Error } & 36 & 164.783 & 4.577 \\\text { Total } & 39 & 213.571 &\end{array}\end{array}$ The interaction term in this model is statistically significant at the 0.05 level. Given this and the scatterplot provided, what should you conclude?

A) The effect of the number of pictures recalled on brainwave relative amplitude is substantially different when subjects are exposed to a stressful stimulus versus a neutral stimulus.
B) The effect of the number of pictures recalled on brainwave relative amplitude is essentially the same when subjects are exposed to a stressful stimulus or a neutral stimulus.
C) The number of pictures recalled does not affect brainwave relative amplitude at all.
D) The type of stimulus received does not affect brainwave relative amplitude at all.