1. The average speed of cars on a highway is 150 km/hr. A sample of 40 cars shows an average speed of 145 km/hr with a standard deviation of 5 km/hr. Assuming a significance of 5% is the expectation of 150 km/hr reasonable?

3. A recent study focused on the number of times men and women who live alone buy take-out dinners in a month. Two samples were taken with the following results.

Men Women

Mean 24 22

Standard Deviation 4 3

Sample Size 35 40

At the 0.05 significance level, is there a difference in the mean number of times men and women order take-out dinners in a month?