The average diameter of washers produced by Machine #2 at the company's Maine plant is known to be 0.5 inches with a standard deviation of 0.015 inches. The most recent quality control test of 80 washers yielded a mean of 0.53 inches with a standard deviation of 0.018 inches. Does the data support that the machine is out of control in that the mean diameter is not 0.5 inches?
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