Question 29:
Find the median from the following frequency distribution:
Class Interval: 20-40 (f = 4), 40-60 (f = 6), 60-80 (f = 10), 80-100 (f = 12), 100-120 (f = 8)
Options :
- a) 82
- b) 80
- c) 78
- d) 75
correct answer : b)
Explanation :
Total frequency N = 4 + 6 + 10 + 12 + 8 = 40. N/2 = 20.
Cumulative frequencies: 4, 10, 20, 32, 40.
The median class is 60-80 with lower limit L = 60, cf preceding = 10, frequency f = 10, class width h = 20.
Median = L + [(N/2 – cf) / f] × h = 60 + [(20 – 10) / 10] × 20 = 60 + 20 = 80.