Question 1
Paper 2Hard6 marksA parcel depot records the dispatch-to-arrival times, in minutes, for equal samples of 60 deliveries on each of two routes. The summaries below give the whisker endpoints, quartiles and any outliers. The outlier is marked with a cross; there are no other outliers.
| Route | Lower whisker | Median | Upper whisker | Outlier | ||
|---|---|---|---|---|---|---|
| A | 12.4 | 18.1 | 22.0 | 26.0 | 29.9 | 54.2 × |
| B | 15.2 | 19.1 | 23.0 | 27.1 | 31.0 | — |
(a)[2]
Calculate the interquartile range for each route. Give your answers in minutes.
(b)[4]
A supervisor concludes that Route A has more variable delivery times and is less likely to have a normally distributed set of times than Route B. Evaluate this conclusion using the summaries.