Shortcut Trick
Arrange Marks (x) in ascending order with their frequencies (f):
8(11), 11(14), 16(9), 20(5), 22(8), 29(3). Total students (N) = 50.
Cumulative Frequency (cf): 11, 25, 34, 39, 47, 50.
For even N, Median = average of (N/2)th and (N/2 + 1)th terms.
Median = (25th term + 26th term) ÷ 2 = (11 + 16) ÷ 2 = 13.5.
∴ The correct answer is 13.5.
Alternate Method
Given: Marks and corresponding Number of Students.
Formula Used: Median for even number of observations (N) = [(N/2)th term + (N/2 + 1)th term] ÷ 2.
⇒ Total Frequency (N) = 11 + 14 + 9 + 5 + 8 + 3 = 50
⇒ Ordered Marks (x): 8, 11, 16, 20, 22, 29
⇒ Cumulative Frequency (cf) calculation:
⇒ For Mark 8: cf = 11
⇒ For Mark 11: cf = 11 + 14 = 25 (This includes the 25th observation)
⇒ For Mark 16: cf = 25 + 9 = 34 (This includes the 26th observation)
⇒ Since N = 50 (even), Median = [Value at 25th pos + Value at 26th pos] ÷ 2
⇒ Median = (11 + 16) ÷ 2 = 27 ÷ 2 = 13.5
∴ The correct answer is 13.5.
Additional Information
Median for Ungrouped Data
If N is odd, Median = ((N+1)/2)th term. If N is even, Median = Average of (N/2)th and (N/2 + 1)th terms.
Empirical Relationship
The relationship between the three measures of central tendency is: Mode = 3 × Median − 2 × Mean.
Median of Grouped Data
Median = l + [(N/2 − cf)/f] × h, where l = lower limit of median class, f = frequency of median class, and h = class width.