Consider the following regression analysis for predicting sales per week from intelligence and extroversion scores:
The regression equation is
Sales/Week = 994 + 8.22 Intelligence + 49.7 Extroversion
Term Coef SE Coef T-Value P-Value
Constant 994 788 1.26 0.224
Intelligence 8.22 7.01 1.17 0.257
Extroversion 49.7 19.6 2.53 0.021
S R-sq R-sq(adj) R-sq(pred)
332.069 35.26% 27.65% 10.66%
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Regression 2 1021166 510583 4.63 0.025
Error 17 1874584 110270
Total 19 2895750
Predicted Values for New Observations
New
Obs Fit SE Fit 90% CI 90% PI
1 2885.62 167.445 (2594.34, 3176.91) (2238.67, 3532.58)
2 3379.99 176.933 (3072.19, 3687.78) (2725.43, 4034.54)
3 2785.05 100.991 (2609.35, 2960.72) (2181.25, 3388.83)
Values of Predictors for New Observations
New
Obs Intelligence Extroversion
1 85 24
2 127 27
3 103 19
What is a 90% confidence interval for the average sales per week for all people with an intelligence score of 103 and an extroversion score of 19?
◦
(2594.34, 3176.91)
◦
(2609.35, 2960.72)
◦
(2181.25, 3388.83)
◦
(3072.19, 3687.78)