If a sample constitutes an appreciable portion of a population, that is, more than 5 percent of the population according to the rule of thumb given on page 239, the formulas of Theorems 11.1 and 11.2 must be modified by using the variance formula of Theorem 8.6 on page 238 instead of that of Theorem 8.1 on page 233. For instance, the maximum error in Theorem 11.1 becomes

Use this modification to rework Exercise 11.20, given that there are 900 sixth graders in the school district.

Transcribed Image Text:

tu