A home building company wishes to determine whether the meantime to frame and roof a new home is 25 or fewer days. The standard deviation, σ, is known to be 3 days.

H0: µ ≤ 25
Ha: µ > 25

A random sample of n = 64 homes provides a sample mean of 26 days. Use the z-critical value approach with an α = 0.10

QUESTION 1: what is the z test statistic?

a) 2.88 

b)1.54 

c) 2.67 

d) 1.26

QUESTION 2: can you reject the null hypothesis?

a) No, we can't reject

b) We can only passively accept the null

c) We don't know because it depends on the confidence interval

d) Yes, we can reject

QUESTION 3: Use the x-bar critical value approach with an α = 0.10, what is the x-bar critical value?

a) 26.28 days 

b) 27.50 days

c) 26 days 

d) 25.48 days