# Find the missing frequencies in the following frequency distribution whose mean is 50 X 10 30 50 70 90 Total F 17 fi 32 F2 19 120

 X 10 30 50 70 90 Total F 17 f1 32 f2 19 120

Given ∑ fi = 120

⇒ 17 + f1 + 32 + f2 + 19 = 120

⇒ f1 +  f2 = 52  ...... (1)

Also,  Solving (1) and (2), we get

f1 = 28 and f2 = 24

• 48

The mean of the following frequency table is 50. But the frequencies f 1 and f 2 in class 20 – 40 and 60 – 80 are missing. Find the missing frequencies. Class Frequency fi Mid-values xi f iui 0-20 17 10 –2 –34 20-40 f 1 30 –1 –f 1 40-60 32 50 0 0 60-80 f 2 70 1 f 2 80-100 19 90 2 38  We have,

N = ∑f i = 120

⇒ 68 + f 1 + f 2 = 120

f 1 + f 2 = 52

Now,

Mean = 50 Solving equation (i) and (ii), we get

f 1 = 28 and f 2 = 24.

• -3

I asked find the missing frequencies in the following frequencies distribution, whose mean is 50.

 x 10 30 50 70 90 Total f 17 F1 32 F2 19 120

I solve it  but it is not coming

I solve it

Fi sum is  68+f1+f2

And fi xi  3580+30f1 +70f2

120 = 68+f1+f2

52 = f1+f2

120=  3580+30f1 +70f2/68+f1+f2

After this I  can not under stand  how the answer is coming  f1 = 28 and f2 = 24

• 11
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