The authors of a certain paper describe a study to evaluate the effect of mobile phone use by taxi drivers in Greece. Fifty taxi drivers drove in a driving simulator where they were following a lead car. The drivers were asked to carry on a conversation on a mobile phone while driving, and the following distance (the distance between the taxi and the lead car) was recorded.

The sample mean following distance was 3.40 meters and the sample standard deviation was 1.13 meters.

(a) Construct a 95% confidence interval (in meters) for 𝜇, the population mean following distance while talking on a mobile phone for the population of taxi drivers.

(b) What assumption must be made in order to generalize this confidence interval to the population of all taxi drivers in Greece?

We need to assume that taxi drivers used in the study are all driving the same make and model car.
We need to assume that taxi drivers used in the study are all using the same mobile phone.
We need to assume that taxi drivers used in the study are representative of all taxi drivers in Greece.
We need to assume that taxi drivers used in the study are representative of all drivers in Greece.
We need to assume that taxi drivers used in the study are representative of all drivers who have used the
simulator.