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प्रश्न
The time taken to assemble a car in a certain plant is a random variable having a normal distribution of 20 hours and a standard deviation of 2 hours. What is the probability that a car can be assembled at this plant in a period of time. Between 20 and 22 hours?
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उत्तर
Let x denotes the time taken to assemable cars mean µ = 20 hours and S.D σ = 2 hours
The standard normal variate
z = `(x - mu)/sigma`
= `(x - 20)/2`
P(Between 20 and 22 hours) = P(20 < x < 22)
When x = 20
z = `(20 - 20)/2 = 0/2` = 0
When x = 22
z = `(22 - 20)/2 = 2/2` = 1
P(20 < x < 22) = P(0 < z < 1)
= 0.3413
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