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Consider the frequency distribution, whe...

Consider the frequency distribution, where A is a positive interger :
`{:("x",A,2A,3A,4A,5A,6A),("f",2,1,1,1,1,1):}`

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The correct Answer is:
C

`therefore sigma^(2)=(sum f_(i)x_(i)^(2))/(n)-((sum f_(i)x_(i))/(n))^(2)`
`implies 160=(92 A^(2))/(7)-((22 A)/(7))^(2)`
`implies 160=(92A^(2))/(7)-(484 A^(2))/(49)`
`implies 160=(644-484)(A^(2))/(49)`
`implies 160=(160 A^(2))/(49)`
`implies A^(2)=49`
`therefore A=7`
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