A U.S. Census Bureau report on the income of Americans says, with 90 percent confidence, the median income of all California households in 2007 was $67,484, with a margin of error of ± $375. This means that:
A) 90 percent of all households had incomes in the range $67,484 ± $375.
B) the median income for all households in the country lies in the range $67,484 ± $375.
C) 90 percent of the households in the sample interviewed by the Census Bureau had incomes in the range $67,484 ± $375.
D) the Census Bureau got the result $67,484 ± $375 using a method that will cover the true median income 90 percent of the time when used repeatedly.

Question

Quizplus · Accepted Answer

The correct interpretation of a confidence interval is that it is a range of values that, based on the sample data, is believed to contain the true population parameter (in this case, median income) with a certain level of confidence (here, 90%). It does not mean that a certain percentage of individual observations fall within this range.

A US Census Bureau Report on the Income of Americans Says