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Find the Mean of Each of the Following Frequency Distributions Class Interval 50-70 70-90 - Mathematics

Find the mean of each of the following frequency distributions

Class interval 50 - 70 70 - 90 90 - 110 110 - 130 130 - 150 150 - 170
Frequency 18 12 13 27 8 22
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Solution

Let the a assumed mean be 100

Class interval Mid-value (x1) d1 = x1 - 100 `"u"_1 = (x_1 - 100)/20` f1 f1u1
50 - 70 60 -40 -2 18 -36
70 - 90 80 -20 -1 12 -12
90 - 110 100 0 0 13 0
110 - 130 120 20 1 27 27
130 - 150 140 40 2 8 16
150 - 170 160 60 3 22 66
        N = 100 `sumf_1"u"_1=61`

A = 100, h = 20

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

`=100+20xx61/100`

`=100+1220/100`

= 100 + 12.20

= 112.20

  Is there an error in this question or solution?
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APPEARS IN

RD Sharma Class 10 Maths
Chapter 15 Statistics
Exercise 15.3 | Q 6 | Page 22
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