Suppose a Normal model describes the number of pages printer ink cartridges last. If we keep track of printed pages for the 47 printers at a company's office, which must be true?
I. The page counts for those ink cartridges will be normally distributed. II. The histogram for those page counts will be symmetric.
III. 95% of those page counts will be within 2 standard deviations of the mean.
A) I, II, and III
B) I only
C) II only
D) none
E) II and III

Question

Quizplus · Accepted Answer

The assumption that the data will be normally distributed or that the histogram will be symmetric is not necessarily true just because a normal model is used to describe the data. The statement about 95% of the data being within 2 standard deviations of the mean is a characteristic of a normal distribution, but without confirming the data actually follows a normal distribution closely, this cannot be assumed to be true for the specific case of the 47 printers.

Suppose a Normal Model Describes the Number of Pages Printer