2025 SJI PRELIMS P2 Q9

School X recorded the time taken by 600 pupils to complete Task A.

1. Use the curve to estimate
   1. the median time,[1]
   2. the interquartile range,[1]
   3. the probability that a randomly chosen pupil took more than 70 minutes.[2]
2. The box plot shows the times for 600 pupils from School Y.
   1. Compare the performance of the two schools.[1]
   2. An outlier lies below \(Q_1-1.5IQR\) or above \(Q_3+1.5IQR\). Explain for which school a time of 88 minutes is more unexpected.[2]
3. For Task B, School X has the same interquartile range but a smaller median. Describe how its cumulative-frequency curve differs.[1]