SOLUTION :
CUMULATIVE FREQUENCY TABLES are in the attachment.
(i)
Here, n = 100
n/2 = 50
Since, the Cumulative frequency just greater than 50 is 65 and the corresponding class is 70 - 90. Therefore 70 - 90 is the median class.
Here, l = 70 , f = 22 , c.f = 43, h = 20
MEDIAN = l + [(n/2 - cf )/f ] ×h
= 70 + [50 - 43)/22] × 20
= 70 + (7 × 20)/22
= 70 + (7 × 10)/11
= 70 + 70/11
= 70 + 6.36
= 76.36
Hence, the Median is 76.36.
(ii)
Here, n = 150
n/2 = 75
Since, the Cumulative frequency just greater than 75 is 105 and the corresponding class is 110 - 120. Therefore 110 - 120 is the median class.
Here, l = 120 , f = 45 , c.f = 60, h = -10 (class interval is in descending order)
MEDIAN = l + [(n/2 - cf )/f ] ×h
= 120 + [75 - 60)/45] × -10
= 120 + (15 × -10)/45
= 120 - 150/45
= 120 - 10/3
= 120 - 3.333
= 111.67 (approximate)
Hence, the Median is 111.67 (approximate)
★★ MEDIAN = l + [(n/2 - cf )/f ] ×h
Where,
l = lower limit of the median class
n = number of observations
cf = cumulative frequency of class interval preceding the median class
f = frequency of median class
h = class size
HOPE THIS ANSWER WILL HELP YOU…