Question

suppose the mean delay at a station for a subway train is 8.2 minutes, with a standard deviation of 2.8 minutes. a subway improvement lobbyist measures the delay of 31 randomly selected trains, and computes the mean delay. this sample mean comes from a normal distribution. what is the mean of this normal distribution?

Answer 1

The mean of the normal distribution representing the sample mean is 8.2 minutes.

The mean of the sampling distribution of the sample mean is equal to the population mean.

In this case, the mean delay at the station for a subway train is 8.2 minutes.

Therefore, the mean of the sampling distribution of the sample mean for a sample size of 31 trains is also 8.2 minutes.

So, the mean of the normal distribution representing the sample mean is 8.2 minutes.