Question

Given below is a frequency distribution with median 46. In this distribution, some of the frequencies are missing. Determine the missing frequencies. |c|c|c|c|c|c|c|c| Marks & 10--20 & 20--30 & 30--40 & 40--50 & 50--60 & 60--70 & 70--80
No. of students & 12 & 30 & x & 65 & y & 25 & 18
Total number of students = 229

• A. 34, 45
• B. 25, 40
• C. 12, 18
• D. 30, 35

Hint:

Median problems require cumulative frequency carefully.

Answer 1

The Correct Option is B

Median class is 40–50 since median = 46. Formula for median: Median = l + (N)/(2) - cff× h Here, l=40, h=10, f=65, N=229, (N)/(2)=114.5 Cumulative frequency before median class: 12+30+x = 42+x Substitute: 46 = 40 + (114.5-(42+x))/(65)× 10 6 = (72.5-x)/(65)× 10 x=25 Using total frequency: 12+30+25+65+y+25+18=229 y=40