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The mean of five observations is 4 and t...

The mean of five observations is 4 and their variance is 5.2. If three of these observations are 2, 4 and 6, then the other two observations are :

A

3 and 5

B

2 and 6

C

4 and 4

D

1 and 7

Text Solution

Verified by Experts

The correct Answer is:
D
`( 2 + 4 + 6 + a + b)/(5) = 4 implies a + b = 8` …….. (i)
` ( 4 + 16 + 36 + a^(2) + b^(2) )/(5) - 16 = 5.2 `
` 56 + a^(2) + b^(2) = 21.2 xx 5`
` a^(2) + b^(2) = 50`
` a^(2) + b^(2) = 50`……… (ii)
Solve (1) and (2) we get
a=1 , b=7 .
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