Researchers Investigated the Effects of Acute Stress on Emotional Picture

Multiple Choice

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 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. Using software, we obtained the following output:

$\begin{array} { l r r } \text { Predictor } & \text { Coef } & \text { SE Coef } \\ \text { Constant } & 4.795 & 1.329 \\ \text { recall } & - 0.1139 & 0.1069 \\ \text { stress } & - 4.262 & 2.205 \\ \text { recall* } \text { stress } & 0.4337 & 0.1677 \end{array}$

A) A confidence interval for the mean brainwave relative amplitude of all adult men in a similar experiment exposed to a neutral stimulus and who remember 10 pictures
B) A confidence interval for the mean brainwave relative amplitude of all adult men in a similar experiment exposed to a stressful stimulus and who remember 10 pictures
C) A prediction interval for the brainwave relative amplitude of one adult man in a similar experiment exposed to a neutral stimulus and who remembers 10 pictures
D) A prediction interval for the brainwave relative amplitude of one adult man in a similar experiment exposed to a stressful stimulus and who remembers 10 pictures