Question

Mean value of the weekly income of 40 families is 265.But in the calculation,income of one family was read as 150 instead of 115.Find the"Corrected"mean. (Solve as per statistics)

Answer 1

let the sum of income 40 families be x

then x/40=265

x=10600

difference in wrongly entered value 150-115=35

So we need to subtract 35 from the total income

i.e. corrected total income=10600-35=10565

Corrected mean = 10565/40= 264.125

Answer 2

The correct mean is 264.15

Given:

Total number of families = mean = 265

Weekly Income = N = 40

The income of one family read incorrect = Incorrect item = 150

Correct item = 115

To Find:

Find the Corrected mean.

Solution:

Calculating the wrong sum -

= Weekly Income x Mean

= 40 x 265

= 10,600

Calculating Correct sum -

= 10600 + Correct item - Incorrect item

= 10,600 + 115 - 100

= 10656

Calculating mean -

= ∑x/N

= 10656/40

= 265.14

Answer: The correct mean is 264. 15

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