1. The height, h cm, of each of 120 plants is measured.
The cumulative frequency diagram shows this information.

Use the cumulative frequency diagram to find an estimate of

i) the median,

   ............................................ cm [1]

ii) the interquartile range,  

............................................ cm [2]

iii) the 60^th percentile,

 ............................................ cm [1]

iv) the number of plants with a height greater than 40cm.

 [2]