The heights of 100 senior-secondary students have been recorded and grouped as follows:
Height (cm): 140–150, 150–160, 160–170, 170–180, 180–190
Number of students: 8, 18, 32, 28, 14
Using this information, complete the tasks below:
(i) Draw the less–than cumulative frequency curve for the data on a suitable scale.
(ii) From the curve, estimate the first quartile Q1 and the third quartile Q3 of the distribution.
(iii) Hence calculate the inter-quartile range of the heights.
(iv) Using the same curve, estimate the height below which 85 % of the students fall.