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) II only
B) II and III
C) I, II, and III
D) none of these
E) I only

Question

Quizplus · Accepted Answer

A normal model describing a population does not guarantee that a sample from that population will be normally distributed or symmetric, especially with a small sample size like 47. Also, the empirical rule (95% within 2 standard deviations) applies to the population, not necessarily to a small sample.

Suppose a Normal Model Describes the Number of Pages Printer