Answer:
4979 is the least number of households that should be surveyed to obtain an estimate that is within $200 of the true mean household income with 95 percent confidence.
Explanation:
We are given the following in the question:
Standard Deviation, σ = $7,200
Margin of error =

We have to find the least number of households that should be surveyed to obtain an estimate that is within $200.
Formula:



4979 is the least number of households that should be surveyed to obtain an estimate that is within $200 of the true mean household income with 95 percent confidence.