Find the Mean of Each of the Following Frequency Distributions 0-10 10-20 20-30 - Mathematics

Find the mean of each of the following frequency distributions

 Class interval 0 - 10 10 - 20 20 - 30 30 - 40 40 - 50 Frequency 9 12 15 10 14

Solution

Let the assumed mean A = 25

 Class interval Mid value(x1) d1 = x1 - 25 "u"_1=(x_1-25)/10 f1 f1u1 0 -10 5 -20 -2 9 -18 10 - 20 15 -10 -1 12 -12 20 - 30 25 0 0 15 0 30 - 40 35 10 1 10 10 40 - 50 45 20 2 14 28 N = 60 sumf_1"u"_1=8

We have

A = 25, h = 10

Mean =A+hxx(sumf_1"u"_1)/N

=25+10xx8/60

=25+80/60

= 25 + 1.333

= 26.333

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APPEARS IN

RD Sharma Class 10 Maths
Chapter 15 Statistics
Exercise 15.3 | Q 9 | Page 23