QNT 561 Week 5 Weekly Learning Assessments 
Chapter 13 Exercise 6
The owner of Maumee FordMercuryVolvo wants to study the relationship between the age of a car and its selling price. Listed below is a random sample of 12 used cars sold at the dealership during the last year. 
Car Age (years) Selling Car Age (years) Selling Price ($000)
Price ($000)
1 9 8.1 7 8 7.6
2 7 6.0 8 11 8.0
3 11 3.6 9 10 8.0
4 12 4.0 10 12 6.0
5 8 5.0 11 6 8.6
6 7 10.0 12 6 8.0
a. If we want to estimate selling price on the basis of the age of the car, which variable is the dependent variable and which is the independent variable?
b1. Determine the correlation coefficient. (Negative amounts should be indicated by a minus sign. Round your answers to 3 decimal places.)
b2. Determine the coefficient of determination. (Round your answer to 3 decimal places.)
c. Interpret the correlation coefficient. Does it surprise you that the correlation coefficient is negative? (Round your answer to nearest whole number.)
Chapter 13 Exercise 12
The Student Government Association at Middle Carolina University wanted to demonstrate the relationship between the number of beers a student drinks and his or her blood alcohol content (BAC). A random sample of 18 students participated in a study in which each participating student was randomly assigned a number of 12ounce cans of beer to drink. Thirty minutes after they consumed their assigned number of beers, a member of the local sheriff’s office measured their blood alcohol content. The sample information is reported below. 
Student Beers BAC Student Beers BAC
1 6 0.1 10 3 0.07
2 7 0.09 11 3 0.05
3 7 0.09 12 7 0.08
4 4 0.1 13 1 0.04
5 5 0.1 14 4 0.07
6 3 0.07 15 2 0.06
7 3 0.1 16 7 0.12
8 6 0.12 17 2 0.05
9 6 0.09 18 1 0.02
Use a statistical software package to answer the following questions. 
a1. Choose a scatter diagram that best fits the data.
b. Fill in the blanks below. (Round your answers to 3 decimal places.)
c. Determine the coefficient of correlation and coefficient of determination. (Round your answers to 3 decimal places.)
c1. State the decision rule for .01 significance level: H0: ρ ≤ 0; H1: ρ > 0. (Round your answer to 3 decimal places.)
c2. Compute the value of the test statistic. (Round your answer to 2 decimal places.)
c3. What is the pvalue? (Hint: use your analysis software) (Round pvalue to 4 decimal places.)
c4. At the .01 significance level, is it reasonable to conclude that there is a positive relationship in the population between the number of beers consumed and the BAC?
Chapter 13 Exercise 14
The following sample observations were randomly selected.
a. Determine the regression equation. (Negative amounts should be indicated by a minus sign. Round your answers to 3 decimal places.) 




b. Determine the value of when X is 7. (Round your answer to 3 decimal places.)
Chapter 13 Exercise 22
The owner of Maumee FordMercuryVolvo wants to study the relationship between the age of a car and its selling price. Listed below is a random sample of 12 used cars sold at the dealership during the last year. 
Car Age (years) Selling Price ($000) Car Age (years) Selling Price ($000)
1 9 8.1 7 8 7.6
2 7 6 8 11 8
3 11 3.6 9 10 8
4 12 4 10 12 6
5 8 5 11 6 8.6
6 7 10 12 6 8
The regression equation is, the sample size is 12, and the standard error of the slope is 0.23. Use the .05 significance level. Can we conclude that the slope of the regression line is less than zero?
Chapter 13 Exercise 26
The owner of Maumee FordMercuryVolvo wants to study the relationship between the age of a car and its selling price. Listed below is a random sample of 12 used cars sold at the dealership during the last year. 
Car Age (years) Selling Price ($000)
1 9 8.1
2 7 6.0
3 11 3.6
4 12 4.0
5 8 5.0
6 7 10.0
7 8 7.6
8 11 8.0
9 10 8.0
10 12 6.0
11 6 8.6
12 6 8.0
a. Determine the standard error of estimate. (Round your answer to 3 decimal places.)
b. Determine the coefficient of determination. (Round your answer to 3 decimal places.)
c. Interpret the coefficient of determination. (Round your answer to the nearest whole number.)
Chapter 14 Exercise 2
Thompson Photo Works purchased several new, highly sophisticated processing machines. The production department needed some guidance with respect to qualifications needed by an operator. Is age a factor? Is the length of service as an operator (in years) important? In order to explore further the factors needed to estimate performance on the new processing machines, four variables were listed:
X1 = Length of time an employee was in the industry
X2 = Mechanical aptitude test score
X3 = Prior onthejob rating
X4 = Age
Performance on the new machine is designated y.
Thirty employees were selected at random. Data were collected for each, and their performances on the new machines were recorded. A few results are: 
Performance Length of Mechanical Prior
on New Time in Aptitude OntheJob
Machine, Industry, Score, Performance, Age,
Name Y X1 X2 X3 X4
Mike Miraglia 112 12 312 121 52
Sue Trythall 113 2 380 123 27
The equation is: 
Ŷ = 11.6 + 0.4X1 + 0.286X2 + 0.112X3 + 0.002X4
a. What is this equation called?
b. How many dependent and independent variables are there?
c. What is the number 0.286 called?
d. As age increases by one year, how much does estimated performance on the new machine increase? (Round your answer to 3 decimal places.)
e. Carl Knox applied for a job at Photo Works. He has been in the business for 6 years and scored 280 on the mechanical aptitude test. Carl’s prior onthejob performance rating is 97, and he is 35 years old. Estimate Carl’s performance on the new machine. (Round your answer to 3 decimal places.)
Chapter 14 Exercise 6
Consider the ANOVA table that follows. 
Analysis of Variance Source DF SS MS F
Regression 5 3710 742 12.89
Residual Error 46 2647.38 57.55
Total 51 6357.38
a1. Determine the standard error of estimate. (Round your answer to 2 decimal places.)
a2. About 95% of the residuals will be between what two values? (Round your answers to 2 decimal places.)
b1. Determine the coefficient of multiple determination. (Round your answer to 3 decimal places.)
b2. Determine the percentage variation for the independent variables. (Round your answer to 1 decimal place. Omit the "%" sign in your response.)
c. Determine the coefficient of multiple determination, adjusted for the degrees of freedom. (Round your answer to 3 decimal places.)
Chapter 14 Exercise 8
The following regression output was obtained from a study of architectural firms. The dependent variable is the total amount of fees in millions of dollars. 
Predictor Co eff SE Co eff t pvalue
Constant 7.987 2.967 2.69 0.01
X1 0.122 0.031 3.92 0
X2 –1.120 0.053 –2.270 0.028
X3 –0.063 0.039 –1.610 0.114
X4 0.523 0.142 3.69 0.001
X5 –0.065 0.04 –1.620 0.112
Analysis of Variance
Source DF SS MS F pvalue
Regression 5 3710 742 12.89 0
Residual Error 46 2647.38 57.55
Total 51 6357.38
X1 is the number of architects employed by the company.
X2 is the number of engineers employed by the company.
X3 is the number of years involved with health care projects.
X4 is the number of states in which the firm operates.
X5 is the percent of the firm’s work that is health care–related.
a. Write out the regression equation. (Round your answers to 3 decimal places. Negative answers should be indicated by a minus sign.)
b. How large is the sample? How many independent variables are there?
c1. State the decision rule for .05 significance level: H0: β1 = β2 = β3 =β4 =β5 =0; H1: Not all β's are 0. (Round your answer to 2 decimal places.)
c2. Compute the value of the F statistic. (Round your answer to 2 decimal places.)
c3. Can we conclude that the set of regression coefficients could be different from 0? Use the .05 significance level.
d1. State the decision rule for .05 significance level. (Round your answers to 3 decimal places.)
d2. Compute the value of the test statistic. (Round your answers to 2 decimal places. Negative answers should be indicated by a minus sign.)
d3. Which variable would you consider eliminating?