A manufacturer of high intensity lamps finds that the useful life of the lamps is normally...

A manufacturer of high intensity lamps finds that the useful life of the lamps is normally distributed with population mean μ = 70 months and population standard deviation s = 12 months. A sample size n = 16 is taken. What is the probability that the sample mean is greater than 75 months?

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Expert Solution

Solution :

Given that ,

mean = = 70

standard deviation = = 12

n = 16

= 70

= / n = / = 12/16 = 3

P( > 75) = 1 - P( <75 )

= 1 - P[( - ) / < (75-70) /3 ]

= 1 - P(z <1.67 )

= 1 - 0.9525 = 0.0475

Probability = 0.0475

orchestra answered 1 year ago

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