In: Statistics and Probability
develop simple linear regression models for predicting sales as a function of the number of each type of ad. Compare these results to a multiple linear regression model using both independent variables. State each model and explain R- square, significance F and P-values.
Concert Sales | ||
Thousands of | Thousands of | |
Sales ($1000) | Radio&TV ads | Newspaper ads |
$1,119.00 | 0 | 40 |
$973.00 | 0 | 40 |
$875.00 | 25 | 25 |
$625.00 | 25 | 25 |
$910.00 | 30 | 30 |
$971.00 | 30 | 30 |
$931.00 | 35 | 35 |
$1,177.00 | 35 | 35 |
$882.00 | 40 | 25 |
$982.00 | 40 | 25 |
$1,628.00 | 45 | 45 |
$1,577.00 | 45 | 45 |
$1,044.00 | 50 | 50 |
$914.00 | 50 | 50 |
$1,329.00 | 55 | 20 |
$1,330.00 | 55 | 20 |
$1,405.00 | 60 | 30 |
$1,436.00 | 60 | 30 |
$1,521.00 | 65 | 35 |
$1,741.00 | 65 | 35 |
$1,866.00 | 70 | 40 |
$1,717.00 | 70 | 40 |
simple linear regression with Sales and Radio & TV adds.
Go to data tab --> choose data analysis and choose regression statistics.
SUMMARY OUTPUT | ||||||||
Regression Statistics | ||||||||
Multiple R | 0.697 | |||||||
R Square | 0.485 | |||||||
Adjusted R Square | 0.460 | |||||||
Standard Error | 14.551 | |||||||
Observations | 22 | |||||||
ANOVA | ||||||||
df | SS | MS | F | Significance F | ||||
Regression | 1 | 3992.393 | 3992.393 | 18.85481532 | 0.00032 | |||
Residual | 20 | 4234.879 | 211.744 | |||||
Total | 21 | 8227.273 | ||||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | Lower 95.0% | Upper 95.0% | |
Intercept | -5.7008932 | 11.67721 | -0.48821 | 0.6307 | -30.05913327 | 18.65735 | -30.0591 | 18.65735 |
Sales ($1000) | 0.039899813 | 0.009189 | 4.342213 | 0.0003 | 0.020732271 | 0.059067 | 0.020732 | 0.059067 |
simple linear regression with Sales and Newspaper adds
SUMMARY OUTPUT | ||||||||
Regression Statistics | ||||||||
Multiple R | 0.264 | |||||||
R Square | 0.070 | |||||||
Adjusted R Square | 0.023 | |||||||
Standard Error | 341.515 | |||||||
Observations | 22 | |||||||
ANOVA | ||||||||
df | SS | MS | F | Significance F | ||||
Regression | 1 | 175143.3 | 175143.3 | 1.501669 | 0.235 | |||
Residual | 20 | 2332649 | 116632.5 | |||||
Total | 21 | 2507793 | ||||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | Lower 95.0% | Upper 95.0% | |
Intercept | 877.2432432 | 293.084 | 2.993146 | 0.007186 | 265.8807233 | 1488.606 | 265.8807 | 1488.606 |
Newspaper ads | 10.20486486 | 8.327607 | 1.225426 | 0.23465 | -7.166218221 | 27.57595 | -7.16622 | 27.57595 |
Multiple linear regression:
SUMMARY OUTPUT | ||||||||
Regression Statistics | ||||||||
Multiple R | 0.738 | |||||||
R Square | 0.544 | |||||||
Adjusted R Square | 0.496 | |||||||
Standard Error | 245.233 | |||||||
Observations | 22 | |||||||
ANOVA | ||||||||
df | SS | MS | F | Significance F | ||||
Regression | 2 | 1365150 | 682574.9 | 11.34994 | 0.0006 | |||
Residual | 19 | 1142643 | 60139.1 | |||||
Total | 21 | 2507793 | ||||||
Coefficients | Standard Error | t Stat | P-value | Lower 95% | Upper 95% | Lower 95.0% | Upper 95.0% | |
Intercept | 385.3814221 | 237.7349 | 1.621055 | 0.121484 | -112.2035109 | 882.9664 | -112.204 | 882.9664 |
Radio&TV ads | 12.03232224 | 2.704913 | 4.448322 | 0.000276 | 6.370874871 | 17.69377 | 6.370875 | 17.69377 |
Newspaper ads | 9.391870119 | 5.982624 | 1.569858 | 0.132952 | -3.129904984 | 21.91365 | -3.1299 | 21.91365 |