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4 votes
The life expectancy of a particular brand of lightbulb is normally distributed with a mean of 1,500 hours and a standard deviation of 75 hours.

What is the probability that a lightbulb will last less than 1,410 hours?


A .1151
B .2671
C .3321
D .4218
E .5111

User BrianMiz
by
7.6k points

1 Answer

4 votes

Explanation:

14 10 is 90 less than the mean 1500

z score = - 90 / 75 = - 1.200

from a z-score table this represents .1151

or 11.51 % will last LESS than 1410 hrs

User Hummmingbear
by
7.5k points
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