The quality control manager at a light bulb factory needs to determine

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?