Consider the following data from a small bookstore.
Number of sales people working-----------------Sales (in $1000)
2--------------------------------------------------------------10
3--------------------------------------------------------------11
7--------------------------------------------------------------13
9--------------------------------------------------------------14
10-------------------------------------------------------------18
10-------------------------------------------------------------20
12-------------------------------------------------------------20
15-------------------------------------------------------------22
16-------------------------------------------------------------22
20-------------------------------------------------------------26
x = 10.4-----------------------------------------------------y = 17.6
SD(x) = 5.64-----------------------------------------------SD(y) = 5.34
1. Calculate the mean and standard deviation of # of sales people (x) and sales (y). Find sample size n.
2. Calculate the correlation coefficient with all three methods (covariance method, z-score method, and correlation tool in Excel).
3. Find b0 and b1 for the linear regression model with all three methods (two different formulas and Solver). Interpret the meaning of b1 of this linear regression model.
4. Calculate Se and SST.
5. Calculate R square with both methods (correlation coefficient method and the formula r square = 1 - SSE/SST). Interpret the meaning of R square of this linear regression model.
6. Use Regression tool in Excel to find b0, b1, SSE, SST, r, R square, and Se.
7. Estimate the sales if the number of sales people working is 8, 13, and 19, respectively.