Question

In: Statistics and Probability

The average number of minutes individuals spend on the computer during a day is 134 minutes...

The average number of minutes individuals spend on the computer during a day is 134 minutes and the standard deviation is 25 minutes. The number of minutes individuals spend on the computer during a day is normally distributed. If one individual is randomly selected, find the probability that their average number of minutes spent on the computer is (Show your work to receive credit):

a) More than 164 minutes

b) Less than 118 minutes

Solutions

Expert Solution

Solution:

Given:  The number of minutes individuals spend on the computer during a day is normally distributed with mean = minutes and standard deviation = minutes.

Part a) one individual is randomly selected, find the probability that their average number of minutes spent on the computer is  More than 164 minutes

n = 1

that is find:

Find z score for

thus we get:

Look in z table for z = 1.2 and 0.00 and find corresponding area.

P( Z < 1.20 ) = 0.8849

thus

Part b) find:

Find z score for

thus we get:

Look in z table for z = -0.6 and 0.04 and find corresponding area.

P( Z< -0.64) = 0.2611

thus


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