The paint used to make lines on roads must reflect enough light to be clearly visible at night. Let μ denote the true average reflectometer reading for a new type of paint under consideration. A test of H0: μ = 20 versus Ha: μ > 20 will be based on a random sample of size n from a normal population distribution. What conclusion is appropriate in each of the following situations?
a. n = 15, t = 3.2, α = .05
b. n = 9, t = 1.8, α = .01
c. n = 24, t = -.2