Explore BrainMass

Estimation of the Population Proportion and Mean

Please see attached worksheet. If you can give me detailed formulas with answers it would be great.

1. The local Tupperware dealers earned these commissions last month:

$4377.47 $3183.76 $1970.16 $2270.88 $3860.06
$2508.55 $1569.64 $4205.30 $1663.68 $3960.71

Assuming the population for the amount of commissions earned by Tupperware dealers last month is known to be normally distributed, create a 95% confidence interval estimate for , the mean amount of commission earned.

You will be asked to identify x-bar, s, , df, t, E and the confidence interval.
(there are seven questions here---and the two below)

2. Assuming the standard deviation for the cost of a bathroom remodel is known to be $545. How large a sample would need to be taken to estimate the mean cost of a bathroom remodel to within $136 with 99% confidence?

3. A researcher is interested in estimating the proportion of employees who are unhappy in their current job. A prior study estimates this proportion at 0.13. How large a sample would need to be taken to estimate this proportion to within 4% with 95% accuracy?


Solution Summary

Step by step method for testing the hypothesis under 5 step approach is discussed here. Excel template for each problem is also included. This template can be used to obtain the answers of similar problems. Sample size calculation and confidence interval construction is also discussed here.