In: Statistics and Probability
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
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