The depth d centimeters of a river was recorded each day during a period of one year (365 days) when the frequency curve
300
frequency 200
100
ie
20
30
40
SO
60
70
depth, d (cm)
(a) Use the cumulative frequency curve to find
the median depth
(i) the inter-quartile range.
(1) the depth at the 40 percentile,
(iv) the number of days when the depth of the river was at least 25 cm.