The quality control manager at a light bulb factory needs to determine whether the mean life of a large shipment of light bulbs is equal to 375 hours. The population standard deviation is 100 hours. A random sample of 64 light bulbs indicates a sample mean life of 350 hours.
a. What are the null and alternate hypotheses?
b. Draw a diagram labeling all axes and the rejection & failing to reject regions.
c. At the .05 level of significance, what is your conclusion? Why?
d. Suppose a Type II error occurs. What might be the consequences of the event and who suffers?