The life expectancy of a typical lightbulb is normally distributed with a mean of 4,000 hours and a standard deviation of 42 hours. What is the probability that a lightbulb will last between 3,875 and 4,055 hours?

a) 0.8835

b) 0.7825

c) 0.9133

d) 0.9035

Question

Mathematics

Felix Rojas

2 August, 17:07

The life expectancy of a typical lightbulb is normally distributed with a mean of 4,000 hours and a standard deviation of 42 hours. What is the probability that a lightbulb will last between 3,875 and 4,055 hours?

a) 0.8835

b) 0.7825

c) 0.9133

d) 0.9035

+4

Answers (1)

Know the Answer?

Kamden · Answer 1

This is the concept of statistics, to solve the question we proceed as follows;

We need to standardize our values;

z (3,875) = (3,875-4000) / 42

z (3,875) = - 2.9762

z (4055) = (4055-4000) / 42=1.3095=1.3

Therefore;

p (3875
=p (-3
=0.9034

The correct answer is D]

The life expectancy of a typical lightbulb is normally distributed with a mean of 4,000 hours and a standard deviation of 42 hours. What is the probability that a lightbulb will last between 3,875 and 4,055 hours?a) 0.8835b) 0.7825c) 0.9133d) 0.9035

The life expectancy of a typical lightbulb is normally distributed with a mean of 4,000 hours and a standard deviation of 42 hours. What is the probability that a lightbulb will last between 3,875 and 4,055 hours?

a) 0.8835

b) 0.7825

c) 0.9133

d) 0.9035