The following data gives the placement statistics for a college. The annual salaries of 100 students (in lakhs) are tabulated along with the number of students in each salary bracket. Find the quartile deviation of the data to the nearest integer.
Salary Bracket(in lpa)0−55−1010−1515−2020−2525−30No. of students382420963
5 lakhs
Class IntervalFrequencyCumulative Frequency0−538385−10246210−15208215−2099120−2569725−303100
N4=25
Therefore, class corresponding to the first quartile is 0-5
Q1=L+N4−c.ff×h=0+25−038×5=3.29 lpa
3N4=75
Therefore, class corresponding to the third quartile is 10-15
Q3=L+3N4−c.ff×h=10+75−6220×5=13.25 lpa
Quartile Deviation=Q3−Q12=13.25−3.292=4.98