Question

Attempt this question on graph paper. 

Age (yrs )	5-15	15-25	25-35	35-45	45-55	55-65	65-75
No.of casualties	6	10	15	13	24	8	7

(1) Construct the 'less than' Cumulative frequency curve for the above data. using 2 cm =10 years on one axis and 2 cm =10 casualties on the other. 

(2)From your graph determine : 

(a)the median 

(b)the lower quartile   

Answer 1

Age (years)	No.of casualties	Cumulative frequency
5-15	6	6
15-25	10	16
25-35	15	31
35-45	13	44
45-55	24	68
55-65	8	76
65-75	7	83

Numberof terms=83 

(1) ∴ Median = `83/2` = 41.5^th term 

Through 41.5^th term mark draw a line parallel to the x-axis which meets the curve at A. draw aaa  prependicular to x-axis which meets it at B. value of B is the  median = 43 

(2) lower Quartile = Q₁=`83/4= 20 3^("th")/4` term = 29

Upper Quartile = `83xx3/4=62 1^("th")/4` term = 53