A psychologist studying the effect of computer games on
psychological well-being plans to measure changes in individuals’
score on a test that measures “subjective happiness” before and
after a 3-hour session of computer gaming. He has 30 volunteers,
all of whom are experienced “gamers.” Before starting the
experiment, he determines that a two-sided test of significance
using 30 subjects and a significance level of = 0.01 against an
effect size of 1 point (on a 10-point happiness scale) only has a
power of 0.29. If he changes the significance level to = 0.05,
what would happen to the power of the test? Explain your reasoning
to receive full credit.