Question

A
professor would like to conduct a regression analysis to determine
whether a student’s final exam score in her class can be predicted
from the student’s midterm score. She records the midterm and final
exam scores of a sample of students in her class. The midterm
scores have a mean of 71.0 and a standard deviation of 9.4. The
final exam scores have a mean of 66.2 and a standard deviation of
10.3. The correlation between midterm and final exam score is
calculated to be 0.84.

What
is the predicted increase in final exam score when a student’s
midterm score increases by one?

Answer #1

Let , X : midterm score

Y : Final exam score

The regression equation is ,

Where , 'b' be the regression coefficient or slope of the regression equation.

and 'a' be the constant or intercept of the regression equation.

Now ,

Therefore , The regression equation is ,

Now , For x=1

Therefore , the predicted increase in final exam score when a student’s midterm score increases by one is 1.7720

A professor knows that her statistics students' final exam
scores have a mean of 78 and a standard deviation of 9.3. In his
class, an "A" is any exam score of 90 or higher. This quarter she
has 25 students in her class. What is the probability that 4
students or more will score an "A" on the final exam?

Professor Elderman has given the same multiple-choice final exam
in his Principles of Microeconomics class for many years. After
examining his records from the past 10 years, he finds that the
scores have a mean of 76 and a standard deviation of 12.
What is the probability that a class of 15 students will have a
class average greater than 70 on Professor Elderman’s final
exam?
rev: 11_19_2018_QC_CS-148628, 02_20_2020_QC_CS-201523

The time taken by a professor to grade a student’s take home
final exam in Organizational Behavior is uniformly distributed
between 30 to 60 minutes. Let X be the time taken to grade a
student’s final exam in Org Behavior. [Be sure to show your
calculations.]
a. Draw the probability distribution of X.
b. What is the probability it will take less than 20 minutes to
grade a student’s exam?
c. What is the expected value of grading time for...

A professor found that historically, the scores on the final
exam tend to follow a normal distribution. A random
sample of nine test scores from the current class had a mean score
of 187.9 points and a sample standard deviation of
32.4 points. Find the 90% confidence interval for the population
mean score of the current class.
A.
[167.81, 207.99]
B.
[ 170.13 , 205.67]
C.
[ 166.73, 209.07]
D.
None of these answers are correct.

Professor Elderman has given the same multiple-choice final exam
in his Principles of Microeconomics class for many years. After
examining his records from the past 10 years, he finds that the
scores have a mean of 76 and a standard deviation of 12.
What is the probability Professor Elderman’s class of 36 has a
class average below 78?
0.5675
0.1587
0.8413
Cannot be determined.

In an introductory stats course x = mid-term score and y =
final-exam score. Both scores have a mean of 80 and a standard
deviation of 10. The correlation between scores is 0.70. Find the
regression equation. What would be the final-exam would be if one
scored a 67 on the mid-term? Assume mid-term scores predict
final-exam scores.

In a statistics course, a linear regression equation was
computed to predict the final-test score from the score on the
first quiz. The resulting equation was: ˆy = 25 + 0.84x with a
correlation of 0.73 where y is the final test score and x is the
score on the first quiz.
(a) If Carla scored 82 points on her first quiz, what is the
predicted value of her score on the final test?
(b) The linear regression line predicted...

Suppose that you are taking a course.
There are two midterms and a final exam. Each midterm impacts 25%
of the course grade while final exam impacts 50% of the grade. The
first and second midterm scores follow a normal distribution with
mean 84 points and the standard deviation of 9 points and mean 85
points and the standard deviation of 6. Assume that the final exam
is also normally distributed with mean 87 and standard deviation of
6 points....

Suppose that your statistics professor tells you that the scores
on a midterm exam were approximately normally distributed with a
mean of 78 and a standard deviation of 7. The top 15% of all scores
have been designated A’s. What is the minimum score that you must
earn in order to receive a letter grade A.

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 ...

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