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In eight throws of a die, 5 or 6 is considered a success. The mean and standard deviation of total number of successes is respectively given by

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Answer (Detailed Solution Below)

Option 2 :
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Detailed Solution

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Concept

When a fair dice is rolled, probability of getting any number is .

Suppose an experiment is repeated n times. Probability of success be p.

If X denote the number of success, then

P(X = k) = C(n, k) × pk (1 – p)n - k , 0 ≤ k ≤ n

where

Mean of X = np

Standard deviation of X 

Calculation

A dice is rolled 8 times so, n = 8.

In a single roll of dice, probability of getting 5 or 6 is

= probability of getting 5 + probability of getting 6

So probability of success 

Correct option is (2).

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