Question

The Premier of Queensland has been told that bus times are improving and in fact the average late arrival time per bus has been going down since the new streamlined timetable commenced on the first day of June.

Analysis of all buses showed that on average they were 2.53 minutes late.

It is known that late arrival times for buses are skewed to the right and it is also known the standard deviation is 1.2 minutes.

During June a random sample of 100 buses had arrival times that were late by an average of 2.32 minutes.

a. The analyst wishes to know whether there is evidence that lateness has decreased in June. Since it is known that lateness is skewed to the right, would this affect your results if a hypothesis test is conducted. Explain briefly.

b. Conduct the hypothesis test, using a level of significance of 5%. Use critical value approach. Remember to show all working and include a sketch.

Answer 1