A plant manufacturers 12 voltage DC Power Supplies. Twoengineers, Kelsier and Dockson, are given access to a batch of 500power supplies to test. Their tests determine the maximum powerthat the power supply can provide for a sustained period oftime.
Kelsier, a newly hired quality control engineer randomly selects10 power supplies from this batch, and his tests results in asample mean of 150.030 W and the sample standard deviation of 3.502W.
Dockson, another quality control engineer has worked for thecompany for a long time, and knows from past experience that theaverage capacity of the power supplies that they make is 151 W andsample standard deviation of 4 W.
Management requires that the maximum power that the DC powersupplies can provide should be at least 148 W during sustained use.Assume that the capacity of power supplies is normallydistributed.
a) How confident is Kelsier that the average maximum power thatthe average power supply of this batch can provide is at least 148Watts?
b) Based on the data provided by Dockson, estimate the number ofpower supplies from the given batch that do not satisfy themanagement requirement. List all your assumptions.
