(a(i))[1]
State which interval is the modal class.
(a(ii))[3]
Calculate an estimated mean time for these athletes.
(a(iii))[2]
Calculate the probability that a randomly selected athlete took less than $60$ seconds to complete the $400\text{ m}$.
(b(i))[1]
Find the median value of the times.
(b(ii))[2]
Find the interquartile range of the data.
(b(iii))[3]
Using the extra information about girls’ times, draw the cumulative frequency curve on the grid above.