31. The number of hours that a light bulb burns before failing varies from bulb to bulb. The distribution of burnout times is strongly skewed to the right. The central limit theorem says that
as we look at more and more bulbs, their average burnout times get ever closer to the mean for all bulbs of this type.
the average burnout times of a large number of bulbs have a distribution of the same shape (strongly skewed) as the distribution for individual bulbs.
the average burnout times of a large number of bulbs have a distribution that is close to normal.