L09 Quiz_ Homework_ Social Science Statistics
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Brigham Young University, Idaho *
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Course
221 C
Subject
Mathematics
Date
Apr 3, 2024
Type
Pages
5
Uploaded by DeaconWolverine3338
L09 Quiz: Homework
Due Feb 10 at 10:59pm
Points 10
Questions 10
Available Jan 31 at 11pm - Feb 10 at 10:59pm
Time Limit None
Allowed Attempts 2
Instructions
This quiz was locked Feb 10 at 10:59pm.
Attempt History
Attempt
Time
Score
LATEST
Attempt 1
28 minutes
10 out of 10
Score for this attempt: 10 out of 10
Submitted Feb 9 at 1:43pm
This attempt took 28 minutes.
Question 1
1 / 1 pts
Correct!
The probability of a type I error.
Preparation
Download the L09 Homework Assignment
(https://byuistats.github.io/BYUI_M221_Book/hp/L09/09_HW_Assignment_A.html) and answer the
questions.
Attempt each problem on your own.
You are encouraged to collaborate with other students after your first attempt.
Download the L09 Homework Answer Key
(https://byuistats.github.io/BYUI_M221_Book/hp/L09/09_HW_Answer_Key_A.html) and check your
answers.
Take the Quiz
You may use your notes, but you should complete the quiz without help from others.
This quiz is a tool to help you and your instructor gauge your progress.
Which one of the following best describes the notion of "the significance level of a hypothesis test?"
The probability of a type II error.
The probability of rejecting , whether it's true or not
The probability of obtaining a test statistic at least as extreme as the one you calculated, assuming the null hypothesis
is true.
Question 2
1 / 1 pts
Correct!
Question 3
1 / 1 pts
Reject because the P-value is less than the significance level.
Reject because the P-value is greater than the significance level.
Fail to reject because the P-value is less than the significance level.
Correct!
Fail to reject because the P-value is greater than the significance level.
Question 4
1 / 1 pts
The true mean hours of sleep a night of college students in the United States is 6.2 hours. Suppose you
want to use a hypothesis test to determine whether the mean hours of sleep a night of BYU-Idaho
students is higher than the national mean. Which of the following pairs of hypotheses is the most
appropriate for addressing this question?
Suppose you're conducting a hypothesis test for one mean, the significance level is , and the
P-value is 0.30. Should you reject or fail to reject , and why?
The probability of a type I error.
The probability of a type II error.
The probability of rejecting , whether it's true or not.
Correct!
The probability of obtaining a test statistic at least as extreme as the one you calculated, assuming the null hypothesis
is true.
Question 5
1 / 1 pts
The students' mean SAT score is greater than 550.
The students' mean SAT score is 574.
The students' mean SAT score is 550.
The students' mean SAT score is 574.
The students' mean SAT score is greater than 550.
The students' mean SAT score is 550.
Correct!
The students' mean SAT score is 550.
The students' mean SAT score is greater than 550.
Question 6
1 / 1 pts
Correct!
Which one of the following best defines the notion of "the P-value of a hypothesis test?"
Use the following information to answer the next 4 questions.
The national mean SAT score in math is 550. Suppose a high school principal claims that the mean SAT
score in math at his school is better than the national mean score. A random sample of 72 students finds
a mean score of 574. Assume that the population standard deviation is . Is the principal's claim
valid? Use a level of significance of .
State the null and alternative hypotheses.
Compute the test statistic for this analysis. Round your answer to 3 decimal places. (Example: 0.398)
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2.036
2.036 (with margin: 0.001)
Question 7
1 / 1 pts
Correct!
0.0209
0.021 (with margin: 0.001)
Question 8
1 / 1 pts
Reject the null hypothesis. There is insufficient evidence to suggest that the students' mean SAT score is greater than
550. The principal was right.
Correct!
Reject the null hypothesis. There is sufficient evidence to suggest that the students' mean SAT score is greater than
550. The principal was right.
Fail to reject the null hypothesis. There is insufficient evidence to suggest that the students' mean SAT score is greater
than 550. The principal was wrong.
Fail to reject the null hypothesis. There is sufficient evidence to suggest that the students' mean SAT score is greater
than 550. The principal was wrong.
Question 9
1 / 1 pts
Correct!
Determine the P-value based on the test statistic. Round your answer to 3 decimal places. (Example:
0.398) State your decision based on the P-value and the level of significance (
) and give your
conclusion in an English sentence.
In another school a similar sample of student SAT math scores was taken. The principal of that school
also believed that his students scored better than the national average. Suppose this principal collected
a simple random sample of student SAT scores in math. The sample data collected had a mean student
SAT score higher than 550 and the calculated P-value indicated that the null hypothesis should be
rejected. In fact, the true population mean of that school's students' SAT scores is the same as the
national mean score. What kind of error has been committed and why?
Type I error because the principal rejected the null hypothesis when it was true.
Type I error because the principal failed to reject the null hypothesis when it was true.
Type II error because the principal rejected the null hypothesis when it was true.
Type II error because the principal failed to reject the null hypothesis when it was true.
Question 10
1 / 1 pts
Correct!
If I somehow reduce the probability of committing a type I error, I increase the probability of committing a type II error.
If I somehow reduce the probability of committing a type I error, I also reduce the probability of committing a type II
error.
The relationship between the two probabilities depends on the way I set up my study.
There is no specific relationship between the two probabilities.
Quiz Score: 10 out of 10
COPYRIGHT 2024 BRIGHAM YOUNG UNIVERSITY-IDAHO
Suppose you're planning a hypothesis test for one mean, and you know that . Which one of the
following correctly expresses the relationship between the probability that you will commit a type I error
and the probability that you will commit a type II error?