Answer to Question #36626 in Statistics and Probability for lucky415263

Question

Consider the example where the average net income for all sole proprietor CPA’s was found to be $74,914 in a survey done five years ago. A new survey is conducted by taking a random sample of 112 currently, practising sole proprietor CPAs to determine if this average net income figure has changed. The sample average net income is calculated to be $78,695, and it is known that the population standard deviation of net incomes for sole proprietor CPA’s is $14,530. Use the sample data to establish if there is sufficient evidence to conclude that the average net income for sole proprietor CPA’s has changed in the last 5 years.