wiz-icon
MyQuestionIcon
MyQuestionIcon
229
You visited us 229 times! Enjoying our articles? Unlock Full Access!
Question

If the median of the following data is 32.5, find the missing frequencies.
Class interval: 0 -10 10 - 20 20 - 30 30 - 40 40 - 50 50 - 60 60 - 70 Total
Frequency: f1 5 9 12 f2 3 2 40

Open in App
Solution

Class interval Frequency Cumulative frequency
0 – 10 f1 f1
10 – 20 5 5 + f1
20 – 30 9 14 + f1
30 – 40 12 (f) 26 + f1
40 – 50 f2 26 + f1 + f2
50 – 60 3 29 + f1 + f2
60 – 70 2 31 + f1 + f2
N = 40

Given

Median = 32.5

The median class = 90 – 40

L = 30, h = 40 – 30 = 10, f = 12, F = 14 + f1

Median=L+N2Ff×h


=>32.5=30+20(14+f1)12×10


32.530=20(14+f1)12×10


2.5×12=(6f1)×10


30=(6f1)×10


3=6f1


f1=3

Given

Sum of frequencies = 40

f1 + 5 + 9 + 12 + f2 + 3 + 2 = 40

3 + 5 + 9 + 12 + f2 + 3 + 2 = 40

34 + f2 = 40

f2 = 40 – 34 = 6

f1 = 3 and f2 = 6


flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Median
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon