A sales manager for an advertising agency believes there is a relationship between the number of contacts that a salesperson makes and the amount of sales dollars earned. A regression analysis shows the following results: Coefficients Standard Error t-Stat p-value
Intercept -12.201 6.560 -1.860 0.100
Number of Contacts 2.195 0.176 12.505 0.000
ANOVA
df SS MS F Significance F
Regression 1.00 13555.42 13555.42 156.38 0.00
Residual 8.00 693.48 86.68
Total 9.00 14248.90
Additional information needed to perform the calculation x=33.4
∑(x−x)^2=2814.4. Rounding to one decimal place, the 95% confidence interval for 30 calls is .