9/27/2018 Graded Quiz Unit 3
MATH 1281 Statistical Inference - Term 1, 2018-2019
Home ► My courses ► MATH 1281 - AY2019-T1 ► 20 September - 26 September ►
Graded Quiz Unit 3
Started on Wednesday, 26 September 2018, 9:40 PM
State Finished
Completed on Wednesday, 26 September 2018, 11:09 PM
Time taken 1 hour 29 mins
Marks 16.00/20.00
Grade 80.00 out of 100.00
Information
A case study that deals with the e ect of prior reputation on the evaluation
of an instructor is presented in Question 11.1 in the book (Section 11.5).
Students were exposed to either one of two conditions, C and P, and were
asked to rate a lecture given by the instructor. It was found that the
average rating among the 25 students that were exposed to condition C
was 2.613 and the average rating among the 24 students that were
exposed to condition P was 2.236. The sample standard deviations were
0.533 and 0.543, respectively.
Question 1 You want to construct a con dence interval for the expected rating of
Correct students that were exposed to condition P. The con dence level of the
Mark 1.00 out of interval should be 80%. The quantile of the t-distribution that should be
1.00 used for the construction is: (Assume a Normal distribution for the rating)
Select one:
a. qt(0.85,23)
b. qt(0.925,24)
c. qt(0.90,23)
d. qt(0.925,23)
The correct answer is: qt(0.90,23)
https://my.uopeople.edu/mod/quiz/review.php?attempt=1415917 1/13
, 9/27/2018 Graded Quiz Unit 3
Question 2 The con dence interval with con dence level of 80% for the expected
Correct rating of students that were exposed to condition P is: (Assume a Normal
Mark 1.00 out of distribution for the rating. Choose the interval closest to the answer)
1.00
Select one:
a. [2.09, 2.38]
b. [2.47, 2.76]
c. [2.14, 2.33]
d. [2.52, 2.71]
The correct answer is: [2.09, 2.38]
Question 3 The con dence interval with con dence level of 75% for the variance of the
Correct rating of students that were exposed to condition P is: (Assume a Normal
Mark 1.00 out of distribution for the rating. Choose the interval closest to the answer)
1.00
Select one:
a. [0.404, 0.805]
b. [0.250, 0.374]
c. [0.219, 0.437]
d. [0.460, 0.689]
The correct answer is: [0.219, 0.437]
Information
Con dence intervals are computed for the expectation and the variance of
a measurement on the basis of 15 observations. The con dence interval
are constructed under the assumption that the measurement has a
Normal distribution. In reality, the distribution of the observations is the
Exponential(1/3) distribution. Recall that the expectation of the
measurement is 3 and the variance is 9. Use simulations to answer the
following questions:
https://my.uopeople.edu/mod/quiz/review.php?attempt=1415917 2/13
MATH 1281 Statistical Inference - Term 1, 2018-2019
Home ► My courses ► MATH 1281 - AY2019-T1 ► 20 September - 26 September ►
Graded Quiz Unit 3
Started on Wednesday, 26 September 2018, 9:40 PM
State Finished
Completed on Wednesday, 26 September 2018, 11:09 PM
Time taken 1 hour 29 mins
Marks 16.00/20.00
Grade 80.00 out of 100.00
Information
A case study that deals with the e ect of prior reputation on the evaluation
of an instructor is presented in Question 11.1 in the book (Section 11.5).
Students were exposed to either one of two conditions, C and P, and were
asked to rate a lecture given by the instructor. It was found that the
average rating among the 25 students that were exposed to condition C
was 2.613 and the average rating among the 24 students that were
exposed to condition P was 2.236. The sample standard deviations were
0.533 and 0.543, respectively.
Question 1 You want to construct a con dence interval for the expected rating of
Correct students that were exposed to condition P. The con dence level of the
Mark 1.00 out of interval should be 80%. The quantile of the t-distribution that should be
1.00 used for the construction is: (Assume a Normal distribution for the rating)
Select one:
a. qt(0.85,23)
b. qt(0.925,24)
c. qt(0.90,23)
d. qt(0.925,23)
The correct answer is: qt(0.90,23)
https://my.uopeople.edu/mod/quiz/review.php?attempt=1415917 1/13
, 9/27/2018 Graded Quiz Unit 3
Question 2 The con dence interval with con dence level of 80% for the expected
Correct rating of students that were exposed to condition P is: (Assume a Normal
Mark 1.00 out of distribution for the rating. Choose the interval closest to the answer)
1.00
Select one:
a. [2.09, 2.38]
b. [2.47, 2.76]
c. [2.14, 2.33]
d. [2.52, 2.71]
The correct answer is: [2.09, 2.38]
Question 3 The con dence interval with con dence level of 75% for the variance of the
Correct rating of students that were exposed to condition P is: (Assume a Normal
Mark 1.00 out of distribution for the rating. Choose the interval closest to the answer)
1.00
Select one:
a. [0.404, 0.805]
b. [0.250, 0.374]
c. [0.219, 0.437]
d. [0.460, 0.689]
The correct answer is: [0.219, 0.437]
Information
Con dence intervals are computed for the expectation and the variance of
a measurement on the basis of 15 observations. The con dence interval
are constructed under the assumption that the measurement has a
Normal distribution. In reality, the distribution of the observations is the
Exponential(1/3) distribution. Recall that the expectation of the
measurement is 3 and the variance is 9. Use simulations to answer the
following questions:
https://my.uopeople.edu/mod/quiz/review.php?attempt=1415917 2/13
