(a(i))[1]
Use the cumulative frequency diagram to obtain an estimate of the median.
(a(ii))[2]
Use the cumulative frequency diagram to obtain an estimate of the interquartile range.
(a(iii))[2]
Use the cumulative frequency diagram to determine how many people had a journey time of $40$ minutes or more.
(b)[1]
Each of the 80 people also note their journey time from work to home on that day. The table shows the results. Jay says: 'The journey times from home to work are more consistent than the journey times from work to home.' Is Jay correct? Explain how you decide.