Question

The daily expenditure of 100 families are given below. Calculate f1 and f2 if the mean daily expenditure is Rs.188

Answer 1

Answer:

Step-by-step explanation:

Missing in question:-

140 -160 = 5

160 -180 = 25

180- 200 = f1

200 - 220 = f2

220 -240 = 5

Answer:-

Adding class mark and fi xi in below in bold respectively.

140 -160 -> 5 -> 150 ->  750

160 -180 -> 25 -> 170 -> 4250

180- 200 -> f1 -> 190 -> 190f1

200 - 220 = f2 -> 210 -> 210f2

220 -240 = 5 -> 230 -> 1150

Sum of all frequencies = 100

∑i fi = 100  .. (1)

∑i = 5 + 25 + f1 + f2 + 5 ...(2)

From (1) and (2)

f1 + f2 = 65

f2 = 65 - f1  ..... (3)

Mean  = ∑ fi xi / ∑fi

188 = (6150 + 190 f1 + 210 f2) / 100

18800 - 6150 = 190 f1 + 210 f2

12650 = 190 f1 + 210 f2 ... (4)

Substituting (3) in (4)

12650 = 190 f1 + 210 (65 - f1)

f1 = 50

Substituting in (3) f2 = 15

f1 = 50,  f2 = 15

Answer 2

Answer:

This how I had solved it