Single-variable data: diagrams and histogramsEdexcel A-Level Maths: Mind map

Exam questions on Single-variable data: diagrams and histograms

1. The durations of phone calls made from an office are shown in a histogram. The bar for calls from 2 to 6 minutes has frequency density 7.5, the bar for calls from 6 to 10 minutes represents 18 calls, and the bar for calls from 10 to 20 minutes has frequency density 1.2.
   Estimate the number of calls that lasted between 8 and 12 minutes.2 marks
2. The marks, out of 50, scored by 11 students in a test were 12, 15, 17, 18, 20, 21, 23, 25, 26, 28 and 45. For this data take the lower quartile to be the median of the lowest five marks and the upper quartile to be the median of the highest five marks. A value is an outlier if it is more than $1.5\times$IQR above the upper quartile or below the lower quartile.
   Show that the mark of 45 is an outlier.2 marks
3. The heights of 100 plants are summarised as follows: 8 plants are under 10 cm, 30 are under 20 cm, 65 are under 30 cm, 90 are under 40 cm and all 100 are under 60 cm. Assume the heights are spread evenly within each class.
   Use linear interpolation to estimate the median height of the plants.3 marks