Chapter 11 Data Analysis and Statistics - 11.4 Select and Draw Conclusions from Samples - 11.4 Exercises - Skill Practice - Page 770: 25

453

The margin of error, which is the difference between the two numbers divided by two, is .047. We use the margin of error equation to find: $$margin\ of \ error =\frac{1}{\sqrt{n}}\\ n=(margin\ of \ error)^{-2} \\ n=(.047)^{-2} \\ n=453$$