A car manufacturer introduced an updated version of one of the firm's models which would run on either diesel or petrol, and tests were carried out to compare fuel consumption. Different employees at the firm each drove the prototype car with one litre of either diesel or petrol and the number of miles traveled recorded.
(i) Which significance test might you use to determine whether there was a difference between the miles travelled by the two versions of the car?
(ii) If the study concluded that there was some evidence to suggest that the prototype travelled further on diesel, what reservations might you have about the study conclusion? How might you improve the experiment?