Highway safety engineers test new road signs, hoping that increased reflectivity will make them more visible to drivers. Volunteers drive through test course with several of new- and old-style signs and rate which type shows up the best.

a) Is this one-tailed or a two-tailed test? Why?
b) In this context, what would a Type I error be?
c) In this context, what would a Type II error be?
d) In this context, describe what is meant by the power of the test.
e) If the hypothesis is tested at 1% level of significance instead of 5%, how will this affect power of the test?
f) Engineers hoped to base their decision on re- actions of 50 drivers, but time and budget constraints may force them to cut back to 20. How would this influence the power of the test? Describe.