Question

The lifetime of bulbs produced by Tariqs lightening company follows a normal distribution with a mean of 3462 hours and a standard deviation 1070 hours. What is the probability that randomly selected bulb will have a lifetime of at most 2800?

Answer 1

What is the probability that a randomly chosen light bulb will have a lifetime of at most 2800 hours?

$μ = 3462 \; hours \\ σ = 1070\;hours \\ P(X<2800) \\ = P(Z< \frac{2800-3462}{1070} )\\ = P(Z<-0.6187) \\ =0.26806 \\$