A Large Manufacturing Plant Has Analyzed the Amount of Time $\bar { x }$

Multiple Choice

A large manufacturing plant has analyzed the amount of time required to produce an electrical part and determined that the times follow a normal distribution with mean time ? = 45 hours. The production manager has developed a new procedure for producing the part. He believes that the new procedure will decrease the population mean amount of time required to produce the part. After training a group of production line workers, a random sample of 25 parts will be selected and the average amount of time required to produce them will be determined. If the switch is made to the new procedure, the cost to implement the new procedure will be more than offset by the savings in manpower required to produce the parts. Use the hypotheses: H_o: ? ? .45 hours and H_a: ? < 45 hours. If the sample mean amount of time is $\bar { x }$ = 43.118 hours with the sample standard deviation s = 5.5 hours, give the appropriate conclusion, for ? = 0.025. ?

A) Do not reject H_o, do not switch to the new procedure.
B) Reject H_o, switch to the new procedure.
C) Reject H_o, do not switch to the new procedure.
D) Do not reject H_o, switch to the new procedure.