A running club recorded the time, t minutes, taken by 60 members to complete a 5 km run, grouped as follows: 20 ≤ t < 25: 8 members, 25 ≤ t < 30: 22 members, 30 ≤ t < 35: 19 members, 35 ≤ t < 40: 11 members. (a) Write down the modal class. (b) Use the midpoint of each class to estimate the mean time taken, giving your answer correct to 1 decimal place. (c) Comment on whether using the midpoints is likely to give an accurate estimate of the mean, given that a runner's finishing time is unlikely to be spread evenly across each 5-minute interval.
(a)Write down the modal class.(2)
(b)Use the midpoint of each class to estimate the mean time taken, giving your answer correct to 1 decimal place.(5)
(c)Comment on whether using the midpoints is likely to give an accurate estimate of the mean, given that a runner's finishing time is unlikely to be spread evenly across each 5-minute interval.(2)
(Total for Question 10 is 9 marks)