STAT 331
Homework 4
A study was conducted to examine the time required to complete a construction project. The
variables in the study were:
Y = time to complete the project in days
X1 = size of the contract in $10,000
X2 = number of work-days adversely affected by weather
X3 = number of subcontractors involved in the project
The data collected can be found in the âHW4 Dataâ document.
The Minitab output for this regression is provided below.
Use the Minitab output to answer the following questions.
1.
2.
3.
4.
5.
What is the predicted value of ?2?
What is the value of SST?
What is the value of MSR?
What is the value of S2?
What is the predicted value of Y when X1 = 7, X2 = 5, and X3 = 3? (round your answer to
two decimal places)
6. What is the residual for the predicted value in question 5? (round your answer to two
decimal places)
7. If we were conducting the hypothesis test H0: ?3 = 0 vs. Ha: ?3 ? 0, what would be the
calculated value of the test statistic? (round your answer to two decimal places)
8. What is the lower bound of a 95% confidence interval for ?3? (round your answer to two
decimal places)
9. What is the upper bound of a 95% confidence interval for ?3? (round your answer to two
decimal places)
10. Multiple choice: Perform a hypothesis test for H0: ?1 = 0 vs. Ha: ?1 ? 0 with alpha = 0.05.
What is your conclusion?
a) Reject H0, there is evidence that X1 is significant to the model.
b) Reject H0, there is not evidence that X1 is significant to the model.
c) Do not reject H0, there is evidence that X1 is significant to the model.
d) Do not reject H0, there is not evidence that X1 is significant to the model.