Consider the following hypotheses: H0: 150 HA: < 150 A sample of 80 observations

Consider the following hypotheses:
H0: µ ≥ 150
HA: µ < 150
A sample of 80 observations results in a sample mean of 144.
The population standard deviation is known to be 28.
a. What is the critical value for the test with α = 0.01 and with α = 0.05?
b. Does the above sample evidence enable us to reject the null hypothesis at α = 0.01?
c. Does the above sample evidence enable us to reject the null hypothesis at α = 0.05?