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In an experiment with 15 observations of...

In an experiment with 15 observations of x the following results were available `sum x^2=2830 sum x=170` one observation that was 20 was found to be wrong and it was replaced by its correct value of 30 Then the corrected variance is (1) `8.33` (2) `78` (3) `188.66` (4) `177.33`

A

`78.0`

B

`188.66`

C

`177.33`

D

`8.33`

Text Solution

Verified by Experts

The correct Answer is:
1
Given n=15 ,`sumx^(2)=2830,sum x=170`
Since one observation 20 was replaced by 30, then
`sumx^(2)=2830-400+900=3330`
`sum x=170-20+30=180`
Var. `sigma^(2)=(sum x^(2))/(n)-((sum x)/(n))^(2)=(3330)/(15)-((180)/(15))^(2)=78`
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