A Manufacturer of Personal Computers Sets Tests Competing Brands and Finds

Multiple Choice

A manufacturer of personal computers sets tests competing brands and finds that the amounts of energy they require are normally distributed with a mean of 285 kwh and a standard deviation of 9.1 kwh. If the lowest 25% and the highest 30% are not included in a second round of tests,what are the upper and lower limits for the energy amounts of the remaining sets?

A) [269.76 300.24]
B) [269.76 289.78]
C) [280.22 289.78]
D) [280.22 300.24]