The researchers cited in the previous problem (Liguori & Robinson, 2001) also examined the effect of caffeine on response time in the driving simulator.
In a similar study, researchers measured reaction time 30 minutes after participants consumed one 6-ounce cup of coffee. Using the same driving simulation task, for which the distribution of reaction times is normal with µ = 400 msec. and s = 40, they obtained a mean of µ = 392 for a sample of n = 36 participants.
a. Are the data sufficient to conclude that caffeine has a significant effect on reaction time? Use a two-tailed test with a = .05.
b. Compute Cohen's d to estimate the size of the effect.
c. Write a sentence describing the outcome of the hypothesis test and the measure of effect size as it would appear in a research report.