Question: People like to speed in your neighborhood. The police install a radar sign in front of your house. You observe the first ten cars passing by at the following speeds: 44, 35, 48, 42, 53, 48, 49, 38, 45, 46. Assume the observations come from a normal distribution with unknown mean and variance.

(a) What is the sample mean of the car speeds?

(b) What is the sample variance of the car speeds?

(c) Please give a 95% confidence interval on the sample mean.