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प्रश्न
Choose the correct option from the given alternatives:
A die is thrown 100 times. If getting an even number is considered a success, then the standard deviation of the number of successes is ______.
पर्याय
`sqrt50`
5
25
10
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उत्तर
A die is thrown 100 times. If getting an even number is considered a success, then the standard deviation of the number of successes is 5.
Explanation:
n = 100
p(getting even number) = `3/6 = 1/2`
q(not even number) = `3/6 = 1/2`
SD = `sqrt(variance(x)) = sqrt(npq)`
= `sqrt(100 xx 1/2 xx 1/2)`
= `sqrt25`
= 5
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Solution:
A pair of dice is thrown 3 times.
∴ n = 3
Let x = number of success (doublets)
p = probability of success (doublets)
∴ p = `square`, q = `square`
∴ x ∼ B (n, p)
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= `square` + `square`
= `2/27`
