Question 5 (5 + 5 = 10 marks) a) An air-conditioning supplier uses two installers. He is interested in comparing the time each installer takes to install an air-conditioning unit. Data concerning installation times was collected over a period of time, and the following results were determined. (Note: the installation times are in hours). Sample Mean Sample Standard deviation Sample Size Installer A 3 1.1952 8 Installer B 4 1.4142 7 Is there evidence, at the 5% level of significance, of a difference in the average time of installation between the two installers? (You may assume that all installation times are normally distributed, and Installer A and Installer B have equal population variances). You may use the following Excel output. t-Test: Two-Sample Assuming Equal Variances Installer A Installer B Mean 3 4 Variance 1.429 2.000 Observations 8 7 Pooled Variance 1.692 Hypothesized Mean Difference 0 df 13 t Stat -1.485 P(T