Question

National Discount has 260 retail outlets throughout the United States. National evaluates each potential location for a new retail outlet in part on the mean annual income of the households in the marketing area of the new locatio National develops an interval estimate of the mean annual income in a potential marketing area after sample of households. taking a random For a marketing area being studied, a sample of 36 households was taken and the sample mean income was $21,100.39. Based on past experience, National Discount assumes a known value of σ-$4500 for the population income standard deviation. a Develop a 90% confidence interval for the mean annual income of households in this marketing area.

Answer 1

Given n-36 T- $21100.39 $4500 find 90% confidance interval of mean annual income is 4500 21100.39 t 1.64* CI 21100.39 t 1230 CI 21100.391230 and CI 21100.39 1230 CI 22330.39 and CI 19870.39 The 90% confidance interval of mean annual income is $22,330.39 and $19,870.39