From the results shown, we can conclude that Calvin is correct.
Why is Calvin correct?
To determine why Calvin is correct, we can begin by calculating the median value for minutes late in winter. This gives us the following;
5, 8, 9, 10, 14, 17, 26, 32, 44, 67
14 + 17/2
= 15.53
We compare this to the value in summer and realize that the median number of minutes late increases.
Also, the train service is less consistent because the range of data in summer is 11 minutes while in winter, it is up to 67 minutes.