Inference for Two Means: Introduction (Old, fast version)

I introduce inference procedures for the difference between two means in the case where the population standard deviations are known. I discuss the sampling distribution of the difference in the sample means, and discuss the confidence interval formula and the hypothesis test of the equality of population means. The Cairo traffic police officer data is simulated data with the same summary statistics as found in: Kamal, A., Eldamaty, S., and Faris, R. (1991). Blood level of Cairo traffic policemen. Science of the Total Environment, 105:165--170.