Question: Age in years of twenty secondary school students visiting the zoo on a week day were recorded. The results were : 12, 16, 10, 19, 17, 10, 10, 11, 11, 11, 11, 12, 12, 11, 12, 13, 12, 14, 15, 18 Construct an ogive and find the median age and the interquartile range of ages.
A ) 10 years, 10 B ) 9 years, 3.5 C ) 10.5 years, 14.0 D ) 11.4 years, 3.7
Steps to derive
2 Draw ogive with the age of students on x - axis and cumulative frequencies on y - axis as shown.
3 Median age (50th percentile) = 11.4 years [From the graph.]
4 25th percentile = Q1 = 10.3 years [From the graph.]
5 75th percentile = Q3 = 14 years [From the graph.]
6 Inter quartile range = IQR = Q3 - Q1 = 14 - 10.3 = 3.7
