The average age of a vehicle registered in the United States is 96 months. Assume the...

The average age of a vehicle registered in the United States is 96 months. Assume the standard deviation is 16 months. If a random sample of 36 vehicles is selected, find the probability that the mean of their age is between 90 and 100 months.

_________Round your answer to 4 decimal places.

Solutions

Expert Solution

Solution :

Given that ,

mean = = 96

standard deviation = = 16

n = 36

= 96

= / $\sqrt$ n= 16 / $\sqrt$ 36=2.67

P(90< <100 ) = P[(90-96) / 2.67< ( - ) / < (100-96) /2.67 )]

= P( -2.25< Z < 1.50)

= P(Z <1.50 ) - P(Z < -2.25)

Using z table

=0.9332-0.0122

probability=0.9210

orchestra answered 1 year ago

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