The mean gross annual incomes of certified plumbers are normally distributed with the mean of $52,000 and a standard dev

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The Mean Gross Annual Incomes Of Certified Plumbers Are Normally Distributed With The Mean Of 52 000 And A Standard Dev 1 (36.85 KiB) Viewed 21 times

The mean gross annual incomes of certified plumbers are normally distributed with the mean of $52,000 and a standard deviation of $4,000. The ship building association wishes to find out whether this number is still accurate. You take a sample of 40 plumber's salaries and find the average to be $53,788. Using a significance level of 0.05, has there been a change in the mean gross annual income of certified plumbers? a. What are the null and alternate hypotheses? (2 points) Ho: (Click to select) (Click to select) 52,000 H1: (Click to select) (Click to select) 52,000 b. What is the level of significance? (1 point) (Round your answer to 2 decimal places.) c. Compute the value of the test statistic? (2 points) (Round your answer to 2 decimal places. Negative values should have a minus sign in front of them) d. Determine the p-value (2 points) (Round your final answer to 4 decimal places.) e. What is your decision regarding the null hypothesis? (1 point) Fail to reject the null. O Reject the null. f. Interpret the result. (2 points)