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Tamil Nadu Board of Secondary EducationHSC Commerce Class 12

The average number of phone calls per minute into the switch board of a company between 10.00 am and 2.30 pm is 2.5. Find the probability that during one particular minute there will be exactly

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Question

The average number of phone calls per minute into the switchboard of a company between 10.00 am and 2.30 pm is 2.5. Find the probability that during one particular minute there will be exactly 3 calls

Sum
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Solution

The average number of phone cells per minute into the switchboard of a company is λ = 2.5

x follows poisson distribution with

P(x) = `("e"^(-lambda) lambda^x)/(x!)`

= `((2^(-2.5) (2.5)^x)/(x!))`

P(exactly 3 calls) = P(X = 3)

= `("e^(-2.5) (2.5)^3)/3`

= `((0.08208) xx 15.625)/6`

= 0.2138

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Chapter 7: Probability Distributions - Exercise 7.2 [Page 160]

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Samacheer Kalvi Business Mathematics and Statistics [English] Class 12 TN Board
Chapter 7 Probability Distributions
Exercise 7.2 | Q 9. (ii) | Page 160

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