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D Question 20 Problem 3. The average starting salary of students who graduated from colleges of Business in 2020 was $48,400. A sample of 100 graduates of 2021 showed an average starting salary of $50,000. Assume the standard de the population is known to be $8,000. We want to determine whether there has been a significant increase in the starting salaries in 2021. Answer the question 3.1 to 3.12 regarding problem 3. Question 3.1. The sample mean in problem 3 follows which of the following probability distribution? Normal distribution t distribution O Binomial distribution O Standard normal distribution D Question 21 Question 3.2. What is the standard deviation of sample mean in problem 3? Question 22 Question 3.3. If we would like to come up a confidence interval estimation of 2021 salary in problem 3 with 95% confidence level, what would be the margin of error? D Question 23 Question 3.4. If we would like to come up a confidence interval estimation of 2021 salary in problem 3 with 95% confidence level, what would be the upper bound of the interval?D Question 24 Question 3.5. If we would like to come up a confidence interval estimation of 2021 salary in problem 3 with 95% confidence level, what would be the lower bound of the interval? D Question 25 Question 3.6. What should be the Null hypothesis for problem 3? O H s 48,400 O H = 48,400 O H 2 48,400 O u * 48,400 D Question 26 Question 3.7. What should be the Alternative hypothesis for problem 3? O H > 48,400 O H = 48,400 O H 2 48,400 O H