Thank you The paint used to make lines on roads must reflect

The paint used to make lines on roads must reflect enough light to be clearly visible at night. Let mu denote the true average reflectometer reading for a new type of paint under consideration. A test of H0: mu = 20 versus Ha: mu > 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? n - 15, t - 3.2, alpha = .05 n - 9, t = 1.8, alpha = .01 n = 24, t = -.2

Solution

a)

df = 15-1 = 14

alpha = 0.05

critical value : 1.761

T = 3.2

since T value is greater than critical value we reject Ho

b)

df = 9-1 = 8

alpha = 0.01

critical value : 2.896

T = 1.8

since T value is less than critical value we fail to reject Ho

c)

we dont need alpha because T is negative

that means that we need to fail to reject Ho because T is lower than any alpha ( significance level)