Question

A business statistics professor would like to develop a regression model to predict the final exam scores for students based on their current GPAs, the number of hours they studied for the exam, the number of times they were absent during the semester, and their genders. The data for these variables are given in the accompanying table. Complete parts a through d below.

Score GPA Hours
Absences Gender

87 3.75 2.0 0
Female

77 3.20 4.5 3
Male

82 3.16 5.0 3
Male

79 3.35 1.5 0
Female

76 2.75 3.5 6
Female

87 3.04 6.5 1
Female

77 2.53 3.0 0
Male

86 2.92 6.0 1
Female

71 2.99 2.0 3
Female

94 3.89 7.5 4
Male

76 2.98 3.0 3
Female

78 2.25 4.0 3
Male

a. Using technology, construct a regression model using all of the independent variables. (Let variable Gen be the dummy variable for gender. Assign a 1 to a male.)Complete the regression equation for the model below, where y=Score,x1=GPA,x2=Hours,x3=Absences,and x4=Gen.

ModifyingAbove y= ___ + ( )x1 + ( ) x2 + ( ) x3 + ( ) x4

(Round to two decimal places as needed.)

b. Interpret the meaning of the regression coefficient for the dummy variable.

c. A test for the significance of the overall regression model shows that it is significant using α=0.10. Using the p-values, identify which independent variables are significant with α=0.10.

d. Construct a regression model using only the significant variables found in part c and predict the average class score for a student who studied 3.5

hours for the class, missed three classes during the semester, has a current GPA of 3.89 , and is female.

Answer #1

Ford would like to develop a regression model that would predict
the number of cars sold per month by a dealership employee based on
the employee's number of years of sales experience (X1), the
employee's weekly base salary before commissions (X2), and the
education level of the employee. There are three levels of
education in the sales force—high school degree, associate's
degree, and bachelor's degree. The following dummy variables have
been defined.
Degree
X3
X4
High School
0
0
Associate's...

A statistics professor would like to build a model relating
student scores on the first test to the scores on the second test.
The test scores from a random sample of 21 students who have
previously taken the course are given in the table. Test Scores
Student First Test Grade Second Test Grade 1 83 59 2 53 75 3 79 65
4 90 59 5 67 67 6 63 72 7 60 69 8 58 72 9 77 66...

A statistics professor would like to build a model relating
student scores on the first test to the scores on the second test.
The test scores from a random sample of 21 students who have
previously taken the course are given in the table.
Test Scores
Student
First Test Grade
Second Test Grade
1
50
70
2
91
58
3
55
74
4
58
65
5
79
60
6
70
60
7
97
48
8
51
73
9
51
73...

44-47. A researcher studying voting behavior ran a logistic
regression model and got the following results. The dependent
variable is Romneyvote, coded 1 if the respondent voted for Romney,
0 if the respondent voted for Obama. Pid3_01, which measures Party
ID, is coded 0=Democrat, 1=Moderate, 2=Republican. Gender is coded
1=male and 2=female. Age is coded 1=17-39, 2=40-59, 3=60+.
Variables in the
Equation
B
S.E.
Wald
df
Sig.
Exp(B)
Step 1a
pid3_01
2.600
.079
1074.482
1
.000
13.467
Gender
-.068
.095...

Question 1
How is a residual calculated in a regression model? i.e. what is
the meaning of a residual?
a)The difference between the actual value, y, and the fitted
value, y-hat
b)The difference between the fitted value, y-hat, and the mean,
y-bar
c)The difference between the actual value, y, and the mean,
y-ba
d)The square of the difference between the fitted value, y-hat,
and the mean, y-bar
Question 2
Larger values of r-squared imply that the observations are more
closely...

Q) Over the past few years the percentage of students who leave
Lakeland College at the end of the first year has increased. Last
year Lakeland started a voluntary one-week orientation program to
help first-year students adjust to campus life. If Lakeland is able
to show that the orientation program has a positive effect on
retention, they will consider making the program a requirement for
all first-year students. Lakeland’s administration also suspects
that students with lower GPAs have a higher...

1. For a pair of sample x- and y-values, what is the difference
between the observed value of y and the predicted value of y? a) An
outlier b) The explanatory variable c) A residual d) The response
variable
2. Which of the following statements is false:
a) The correlation coefficient is unitless. b) A correlation
coefficient of 0.62 suggests a stronger correlation than a
correlation coefficient of -0.82. c) The correlation coefficient,
r, is always between -1 and 1....

Bivariate Data & Probability
After completing the calculation by hand in Q1 you can use
Excel to check your answers before submitting. Q2 assesses your
general understanding of probability and linear associations using
Excel to analyse a large dataset.
Question 1
Covariance and Correlation
The table below shows a set of sample bivariate data. Calculate
the covariance and correlation coefficient by completing the below
table. Show all working.
X
Y
(X - )
(Y - )
(X - )(Y -...

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