Question

In a malaria epidemic the cases diagonsed were as follows

Date (July) Number

1 5

2 12

3 20

4 27

5 46

6 30

7 31

8 18

9 11

10 5

11 0

12 1

With the help of an ogive .. find on what days does the mode , upper quartile and lower quartile occur...?

Answer 1

solution -
mode = (5+12+20+27+46+30+31+18+11+5+0+1)/12
mode = 206/12
mode = 17.16

upper quartile = 3*(n+1)/4 th value
= 3*(12+1)/4 th value
= (3*13)/4 the value
= 9.75 th value
= (11+5)/2 (Average of 9th and 19th value)
= 16/2
= 8

lower quartile = 1*(n+1)/4 th value
= (12+1)/4 th value
= 13/4 th value
= 3.25 th value
= (20+27)/2 (Average of 3rd and 4th value)
= 23.5