(2 points)

A laser printer is advertised to print text documents at a speed of 18 ppm (pages per minute). The manufacturer tells you that the printing speed is actually a Normal random variable with a mean of 17.48 ppm and a standard deviation of 4.78 ppm. Suppose that you draw a random sample of 44 such printers.

Part i)Using the information about the distribution of the printing speeds given by the manufacturer, find the probability that the mean printing speed of the sample is greater than 18.44 ppm. (Please carry answers to at least six decimal places in intermediate steps. Give your final answer to the nearest three decimal places).

Probability (as a proportion)___________________

Part ii)Using the Normal approximation, which of the following is the probability that more than 46% of the sampled printers operate at the advertised speed (i.e., the printing speed is equal to or greater than 18 ppm)?

A.0.4824

B.0.4912

C.0.6705

D.0.5176

E.0.3295