please help me solve this problem! the first picture is context to help solve 16

Use the following scenario for the next 4 questions. Historically, employees at a local grocery store earned, on average, $25,000 per year, and the standard deviation (0) has been $8,750. The manager of the grocery store thinks that the average salary has changed, but is not sure if it has increased or decreased. To test this, the manager selects a random sample of 49 employees, and finds the sample mean salary to be $28,000. Use a 5% significance level. Question 16 O out of 6.8 points What is/are the critical values? Selected Answer: z= 1.65 Answers: z= 1.65 t= +2.01 t= +1.68 z= +1.96