A spokesman for the city council claims that male and female officers wait equal times for promotion in the police department but the evidence may suggest otherwise. Suppose the standard deviation for waiting for promotion times is 2.5 years. The two samples were selected randomly and the times between promotions (in years) for both samples were recorded as follows: Male officers: 13 8 13 11 11 12 10 11 8 11 14 15 12 9 10 10 12 10 14 13 12 10 12 8 8 11 11 16 7 7 9 5 14 10 8 10 10 (Note: The average and the standard deviation of the data are respectively 10.7 years and 2.42 years.) Female officers: 11 17 11 13 5 10 8 11 11 10 9 10 10 11 3 9 11 16 13 11 9 10 10 10 8 11 12 11 10 12 10 10 7 10 13 10 10 11 10 11 9 12 9 7 10 (Note: The average and the standard deviation of the data are respectively 10.1 years and 2.36 years.) Use 5% level of significance to decide whether there is sufficient evidence that in the police department the mean time between promotions for males is different from the mean time between promotions for females. Procedure: |Select an answer Assumptions: (select everything that applies) Independent samples O The number of positive and negative responses are both greater than 10 for both samples Normal populations O Sample sizes are both greater than 30 Population standard deviations are known Paired samples Simple random samples Population standard deviation are unknown but assumed equal Population standard deviation are unknown