Laboratory tests show that the lives of light bulbs are normally distributed with a mean of 750 hours and a standard deviation of 75 hours. find the probability that a randomly selected light bulb will last between 900 and 975 hours.

0.0214

Step-by-step explanation:

It has been given that

The z-score of normal distribution is given by

Now, for x = 900

Now, for x = 975

Now, from the standard normal table,

The probability for z = 2 is 0.97725

And probability for z = 3 is 0.99865

Therefore, probability that a randomly selected  light bulb will last between 900 and 975  hours is given by

0.99865 - 0.97725

= 0.0214

its 50 miles away from the starting point