Question 1. Data for two variables, x and y, follow.
| xi |
1
|
2
|
3
|
4
|
5
|
| yi |
3
|
7
|
5
|
11
|
14
|
a. Develop the estimated regression equation for these data.
b. Plot the residuals against ". Does the residual plot support the assumptions about e? Explain.
c. Plot the standardized residuals against". Do any outliers appear in these data? Explain.
2. Consider the following data for two variables, x and y.
| x |
22
|
24
|
26
|
30
|
35
|
40 |
| y |
12
|
21
|
33
|
35
|
40
|
36 |
a. Develop an estimated regression equation for the data of the form y' = b0 + b1x.
b. Using the results from part (a), test for a significant relationship between x and use a = .05.
c. Develop a scatter diagram for the data. Does the scatter diagram suggest an estimate regression equation of the form y' = bo + b1x + b2x2? Explain.
d. Develop an estimated regression equation for the data of the form y' = bo + b1x + b2V2
e. Refer to part (d). Is the relationship between x, x2, and y significant? Use a = .05.
f. Predict the value of y when x = 25.
3. Write a multiple regression equation that can be used to analyze the data for a two-factoall design with two levels for factor A and three levels for factor B. Define all variables.