In: Statistics and Probability
Customer # | Order Size (Quantity) | Total Cost of Order | |
10211 | 28 | 1631 | |
10212 | 31 | 1923 | |
10213 | 43 | 2070 | |
10214 | 47 | 2392 | |
10215 | 32 | 1886 | |
10216 | 43 | 2307 | |
10217 | 25 | 1486 | |
10218 | 46 | 2448 | |
10219 | 41 | 2210 | |
10220 | 48 | 2401 | |
10221 | 29 | 1860 | |
10222 | 32 | 1786 | |
10223 | 49 | 2485 | |
10224 | 44 | 2203 | |
10225 | 33 | 1855 | |
10226 | 46 | 2380 | |
10227 | 42 | 2102 | |
10228 | 31 | 1683 | |
10229 | 30 | 1706 | |
10230 | 35 | 1955 | |
10231 | 34 | 1992 | |
10232 | 33 | 1926 | |
10233 | 27 | 1852 | |
10234 | 32 | 1807 | |
10235 | 31 | 1880 | |
10236 | 42 | 2134 | |
10237 | 39 | 1979 | |
10238 | 36 | 1882 | |
A company would like to estimate its total cost equation using customer records. The company has randomly sampled 28 customer records. Each customer record contains a Customer #, the Order Size, and the Total Cost of the Order. The analyst remembers from accounting and economics classes taken in college that
TOTAL COST = Fixed Costs + Variable Cost per Unit *Order Size.
The analysis sees that this is a linear relationship where the TOTAL COST depends on the Fixed Costs, which do not depend on order size, and a variable cost per unit, which is multiplied by the Order Size. The analysis decides to use simple linear regression to estimate the firm’s Total Cost function. Use the data file, Estimating a Total Cost Regression Model.xlsx to answer the following questions:
(a) Total Cost is the dependent variable and the order size is the independent variable.
(b) Steps: Enter the data correctly into the excel sheet from A1. Now go to Data, select Data Analysis and then select Regression. In the new dialogue box which appears, enter the Y range as $C$1:$C$29 and the X range as $B$1:$B$29, check the check boxes of Labels, Confidence interval and give it as 95%. Click on OK.
The estimated regression equation is :
(c) Hence, the estimated fixed cost is obtained as 725.6413209
(d) The estimated average unit variable cost for the company is 34.89119826.
(e) The upper 95% of the confidence interval for the true average unit variable cost for the company is
39.85841299 |
The lower 95% of the confidence interval for the true average unit variable cost for the company is
29.92398354 |
Thus the 95% confidence interval for the true average unit variable cost for the company is (29.92398354,39.85841299)
(f) The SS due to regression is
1683962.625 |
and the total SS is
1893978.679 |
Hence the required percentage is
(g) Enter the revised output as 30 for the entire dataset. Carry out the regression in the same way as instructed in (a) with the revised output as the independent variable. Hence the 95% confidence interval for the intercept, equivalent to the mean total is then given by:
Lower 95% | Upper 95% |
1903.065665 | 2112.72005 |
Hopefully this will help you. In case of any query, do comment. If ou are satisfied with the answer, give it a like. Thanks.