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JEE Main20204 Sep 2020Evening ShiftMathematicsStatisticsActual

If the variance of the following frequency distribution: Class: 10 - 20                 20 - 30                 30 - 40 Frequency: 2                                   x                         &#

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0

Step-by-step solution

Given data can also be expressed as: x i 15 25 35 f i 2 x 2 So, x ¯ = ∑ f i x i Σ f i = 30 + 25 x + 70 4 + x = 25 4 + x 4 + x = 25 Now, σ 2 = 50 = ∑ f i x i 2 Σ f i - x ¯ 2 50 = 450 + 625 x + 2450 4 + x - 25 2 ⇒ 50 = 2900 + 625 x 4 + x - 625 ⇒ 675 ( 4 + x ) = 2900 + 625 x ⇒ 50 x = 200 ⇒ x = 4

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