Can you help me with this problem?

The School Division Superintendent claims that elementary teachers work an average of 40 hours per wee during the school year. A Superintendent of a certain province surveyed 20 randomly selected teachers and found that they work for an average of 41.5 hours a week with a standard deviation of 2.5 hours. Test if the mean number of the teachers' work hours recorded by the supervisor's school district differs from the recorded national average. Use a=0.05.

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