10.44 Paint used to paint lines on roads must reflect enough light to be clearly visible at night. Let m denote the mean reflectometer reading for a new type of paint under consideration. A test of H0: m 5 20 versus Ha: m . 20 based on a sample of 15 observations gave t 5 3.2. What conclusion is appropriate at each of the following significance levels?

a. a 5 .05

c. a 5 .001

b. a 5 .01