The life of light bulbs is distributed normally. the standard deviation of the lifetime is 25 hours and the mean lifetime of a bulb is 590 hours. find the probability of a bulb lasting for at most 622 hours. round your answer to four decimal places.

The probability is 0.8997.

We will use a z-score to answer this question.  z-scores are given by the formula


With our information, we have


Looking this up in a z-table (http://www.z-table.com) we see that the area to the left of this (everything less than, up to this value) is 0.8997.

Just tell koda to adjust the number of shapes himself.

Use photo math it