Question

QUESTION 15 (B. 2/4) Answer the following questions using data from the Police-Public Contact Survey. Are there differences between time of day and how long a police- stop lasts? Group Statistics Was stop during the day or at night N Day 84 Night 124 Std Deviation 25.624 17.588 Mean 15.05 12.12 Sed. Error Mean 2.796 1.579 How many minutes did the stop last? Independent Samples Test Levene's Test for Equality of Variances t-test for Equality of Means 95% Confidence intervalo the Difference Lower Upper Sig. 12- F 2.810 Sie 095 df 200 Mean Difference 2.927 Sud. Error Difference 2.995 .977 How many minutes did the stop last Equal variances assumed Equal variances not assumed 135.146 2.927 -3.424 3.211 Question: What is X1 - 22

Answer 1

We are given the output for the 95% confidence interval of differences using the two methods: Equal variance assumed vs unequal variances for the two populations.

Note that the difference in sample means remains same in both the cases which is given as the Mean difference = 2.927

Therefore 2.927 is the required difference here, this is the point estimate for the difference in population means here.