The file P08_23.xlsx contains data from a survey of 500 randomly selected households.

a. Separate the households in the sample by the location of their residence within the given community. For each of the four locations, use the sample information to calculate a 90% confidence interval for the mean annual income (sum of first income and second income) of all relevant households. Round your answers to the nearest whole dollar, if necessary.

Total income SW Sector NW Sector NE Sector SE Sector

Lower Limit $

$

$

$

Upper Limit $

$

$

$