The mean income per person in the United States is $41,500, and the distribution of incomes follows a normal distribution. A random sample of 10 residents of Wilmington, Delaware, had a mean of $47,500 with a standard deviation of $10,600. At the 0.010 level of significance, is that enough evidence to conclude that residents of Wilmington, Delaware, have more income than the national average?

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Alexis Ware

23 February, 01:53

The mean income per person in the United States is $41,500, and the distribution of incomes follows a normal distribution. A random sample of 10 residents of Wilmington, Delaware, had a mean of $47,500 with a standard deviation of $10,600. At the 0.010 level of significance, is that enough evidence to conclude that residents of Wilmington, Delaware, have more income than the national average?

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Roselyn Simon · Answer 1

0.010 level of significance = z value of - 2.33

41,500-47,500 / (10,600/3.1) = - 1.754

Z value is less than - 2.33 which means that there is not enough evidence to conclude that residents of wilmington have more income than the national average at significance level of 0.010