Exercise 2.23 on page 57 introduces a study in which 40 participants are trained to solve problems in a certain way and then asked to solve an unfamiliar problem that requires fresh insight. Half of the participants were randomly assigned to receive electrical stimulation of the brain while the other half (control group) received sham stimulation as a placebo. The results are shown inTable 4.14.

(a) Use StatKey or other technology to create a randomization distribution to test whether the proportion able to solve a problem is significantly higher in a group receiving electrical stimulation of the brain. Be sure to state the hypotheses, give the p-value, and clearly state the conclusion in context.
(b) Can we conclude that electrical stimulation of the brain helps people solve a new problem that needs fresh insight?

Exercise 2.23 

If we have learned to solve problems by one method, we often have difficulty bringing new insight to similar problems. However, electrical stimulation of the brain appears to help subjects come up with fresh insight. In a recent experiment conducted at the University of Sydney in Australia, 40 participants were trained to solve problems in a certain way and then asked to solve an unfamiliar problem that required fresh insight. Half of the participants were randomly assigned to receive non-invasive electrical stimulation of the brain while the other half (control group) received sham stimulation as a placebo. The participants did not know which group they were in. In the control group, 20% of the participants successfully solved the problem while 60% of the participants who received brain stimulation solved the problem.

Treatment Solved Not Solved Sham Electrical 4 16 12