3) In a 2020 survey of 600 motorcyclists, 404 wear a helmet. In another survey 500 motorcyclists taken a year earlier, 317 wore a helmet. Use a 0.05 significance level to test the claim that the proportion of motorcyclists who wear a helmet was greater in 2020.

4) The ages of randomly selected cars and taxis in Dublin Ireland is given below. Use a 0.05 significance level to test the claim that the mean age of cars is greater than the mean age of taxis. Cars 4 0 8 11 14 3 4 4 3 5 8 3 3 7 4 6 6 1 8 2 15 11 Taxis 8 8 0 3 8 4 3 3 6 11 7 7 6 9 5 3 4 3