Suppose that a brand of lightbulb lasts on average 2813 hours with a standard deviation of 275 hours

Question

Suppose that a brand of lightbulb lasts on average 2813 hours with a standard deviation of 275 hours. Assume the life of the lightbulb is normally distributed. Calculate the probability that a particular bulb will last from 2021 to 3195 hours?

P(2021 < X < 3195) 

Answer 1

You need P ( 2021 < X < 3195)

So on a TI-84

2nd VARS

normalcdf

lower = 2021

upper = 3195

mean = 2813

standard deviation = 275

hit paste twice