Cumulative frequency and box plotsIB MYP Maths Extended: Flashcards

Exam questions on Cumulative frequency and box plots

1. Forty students at a school in Mumbai recorded how long they spent on homework one evening. The cumulative frequencies are: 0 students up to 10 minutes, 5 up to 20 minutes, 10 up to 30 minutes, 20 up to 40 minutes, 30 up to 50 minutes, 38 up to 60 minutes and 40 up to 70 minutes.
   Find the lower quartile, the upper quartile and the interquartile range of the times.2 marks
2. Two takeaway restaurants, X in Lagos and Y in Cairo, record their delivery times in minutes. Restaurant X: minimum 12, lower quartile 18, median 25, upper quartile 34, maximum 52. Restaurant Y: minimum 15, lower quartile 22, median 26, upper quartile 30, maximum 38.
   A customer needs a delivery within 30 minutes. Use the quartiles to explain which restaurant is more likely to deliver in time.2 marks
3. A courier in Singapore weighs 50 parcels. The masses $m$ (in kg) are grouped as follows: $0<m\le2$: 4 parcels; $2<m\le4$: 11 parcels; $4<m\le6$: 17 parcels; $6<m\le8$: 12 parcels; $8<m\le10$: 6 parcels.
   Work out the cumulative frequencies and write down the coordinates you would plot on a cumulative frequency graph, starting at $(0,0)$.3 marks