A company makes batteries that have life spans with a mean of 3000 hours and standard...

A company makes batteries that have life spans with a mean of 3000 hours and standard deviation of 70 hours. Find the probability that the mean life span of a random sample of 85 batteries will be over 3020 hours.

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Expert Solution

Solution :

Given that,

mean = = 3000

standard deviation = = 70

n=85

= =3000

= / n = 70/ 85 = 7.59

P( > 3020) = 1 - P( < 3020)

= 1 - P[( - ) / < (3020 - 3000) /7.59 ]

= 1 - P(z < 2.64)

Using z table

= 1 - 0.9959

probability=0.0041

orchestra answered 1 year ago

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