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Find the Mean of Each of the Following Frequency Distributions Class Interval: 10-30 30-50 50-70 70-90 90-110 110- 130 Frequency: 5 8 12 20 3 2 - CBSE Class 10 - Mathematics

Question

Find the mean of each of the following frequency distributions

 Class interval 10 - 30 30 - 50 50 - 70 70 - 90 90 - 110 110 - 130 Frequency 5 8 12 20 3 2

Solution

Let the assume mean A = 60

 Class interval Mid value(x1) d1 = x1 - 60 "u"_1=(x_1-60)/20 f1 f1u1 10 - 30 20 -40 -2 5 -10 30 - 50 40 -20 -1 8 -8 50 - 70 60 0 0 12 0 70 - 90 80 20 1 20 20 90 -110 100 40 2 3 6 110 - 130 120 60 3 2 6 N = 50 sumf_1"u"_1=14

We have

A = 60, h = 20

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

=60+20xx14/50

=60+280/50

= 60 + 5.6

= 65.6

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Solution Find the Mean of Each of the Following Frequency Distributions Class Interval: 10-30 30-50 50-70 70-90 90-110 110- 130 Frequency: 5 8 12 20 3 2 Concept: Mean of Grouped Data.
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