In a study of the effect of tomoxetine as an alternative treatment for attention deficit hyperactivity disorder (ADHD), researchers Spencer et al. (The American Journal of Psychiatry, 1998) recruited men and women diagnosed with ADHD. All participants were administered tomoxetine and a placebo—each for three weeks in a random order and with a week of washout period between the two treatments. The researchers noted that the average increase in standing heart rate when on tomoxetine compared to when on the placebo was 11 beats per minute, with a standard deviation of 15.05 beats per minute, for a sample of 18 individuals. The distribution of differences in standing heart rate is approximately symmetric.
a. Define, in words, the appropriate parameter(s) of interest in the context of the study. Also, state the appropriate symbol(s) to denote the parameter(s).
b. State, using the symbol(s) described in part (a), the appropriate null and alternative hypotheses to test whether the use of tomoxetine causes an increase in standing heart rate.
c. State the validity conditions that have to be met to be able to perform a theory-based test to test the hypotheses stated in part (b). Are these conditions met? How are you deciding?

d. Regardless of your answer to part (c), perform a theory-based test to test the hypotheses stated in part (b). Be sure to report a test statistic value and a p-value in your answer.

e. Interpret your p-value in the context of the study.

f. Find a 95% confidence interval for the parameter of interest.
g. Provide a full (four-part) conclusion, including comments on significance, estimation, causation, and generalization.