The lifetime of a certain type of calculators is normally distributed. If the mean is 400 hours and the standard

The lifetime of a certain type of calculators is normally distributed. If the mean is 400 hours and the standard deviation is 50 hours, for a group of 5000 batteries, how many are expected to last

1.between 350 hrs to 450 hours
2.more than 300 hours
3.less than 300 hours

Leave a Reply

Your email address will not be published.