The number of litres of petrol purchased by a random sample of motor vehicle drivers is shown below: Questions:
a)Find the mean
b)Find the standard deviation
c)Find the unbiased estimates of the mean and variance for the population this sample comes from.

Mozart lenses inc. recently introduced seelites, a thinner lens for eyelasses. of a sample of 800 eyeglass wearers, 246 said they would purchases their next pair of eyeglasses with the new lenses. lenses inc. estimates that the number of people who purchase eyeglasses in a year is 1,700,000. most eyeglasses wearer buy one new pair of eyeglasses a year. what is the annual sales potential for the new lenses.

Which of the following is the shape of a cross section of the figure shown below

Identify the number as a rational or irrational.explain. 127