QJEEM19Ma0348: JEE Main 2019 Mathematics - Class 11 JEEM19Ma0348 Solution: The outcome of each of 30 items was observed; 10 items gave an…

Question

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The outcome of each of 30 items was observed; 10 items gave an outcome

{1 \over 2}

– d each, 10 items gave outcome

{1 \over 2}

each and the remaining 10 items gave outcome

{1 \over 2}

+ d each. If the variance of this outcome data is

{4 \over 3}

then |d| equals :

Accepted Answer

Variance is independent of region. So we shift the given data by

{1 \over 2}

.

so,

{{10{d^2} + 10 \times {0^2} + 10{d^2}} \over {30}} - {\left( 0 \right)^2} = {4 \over 3}

\Rightarrow

d²

=

2

\Rightarrow

\left| d \right| = \sqrt 2

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