18 7 Trains arrive into stations either early, on time or late. An early arrival is recorded as a negative delay. An on-time arrival is recorded as zero delay. A late arrival is recorded as a positive delay. Richard has collected samples of train delays on two routes, for those ‘morning rush’ trains scheduled to depart between 0631 and 0830 on weekdays in summer 2019. These two routes will be the only routes considered in this question. The routes are • Southend‑on‑Sea to London Liverpool Street, • Brighton to London Victoria. The total timetabled journey time on both routes is between 1 hour and 1 hour 5 minutes. You may assume that Richard’s samples are random. The delays, to the nearest minute, are plotted on the frequency polygons. 14 12 10 8 6 4 2 0 –5 –4 –3 –2 –1 0 1 2 3 4 5 6 7 8 9 10 11 12 Frequency Trains from Southend‑on‑Sea to London Liverpool Street Trains from Brighton to London Victoria Train delays on arrival at London station (minutes) Samples of ‘morning rush’ trains to London [Data source: recenttraintimes.co.uk] Richard has calculated these sample statistics. Delay in minutes Trains from Southend‑on‑Sea to London Liverpool Street Trains from Brighton to London Victoria mean –0.709 3.39 standard deviation 2.45 3.10 sample size 55 56 Figure 5