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

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

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`