SD = sq rt of 225 = 15
Z = (score-mean)/SD
Look in the back of your statistics textbook for a table called something like “area under normal distribution” to find the proportion/probability related to the Z score.
The life of light bulbs is distributed normally. The variance of the lifetime is 225 and the mean lifetime of a bulb is 590 hours. Find the probability of a bulb lasting for at most 607 hour
1 answer
3 answers