Given that t<span>he
mean lifespan of a sylvania light bulb is 1600 hours with a standard
deviation of 300 hours, an iqr of 450 hours, and a range of 690 hours.
the lifespan distribution is relatively symmetric.
Since, the distribution is relatively symmetric, the measure of
spread that is the best measurement is the standard deviation.</span>
She should use Mean. That is when you add together all of the numbers, then divide by the number of numbers. Her average grade is 80.75, or rounded it is 81.
