A factory produces plate glass with a mean thickness of 4 mm and a standard deviation of 1.1 mm. A simple random sample of 100 sheets of glass is to be measured, and the sample mean thickness of the 100 sheets x is to be computed. We know the random variable x has approximately a Normal distribution because of the a. law of proportions.
b. law of large numbers.
c. central limit theorem.
d. fact that probability is the long run proportion of times an event occurs.
e. fact that a random sample was selected.