Quiz 2_ Attempt review _ Courses 2023-2024

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North Carolina State University *

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311

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Statistics

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Apr 3, 2024

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3/28/24, 1:09 PM Quiz 2: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1453498&cmid=955444 1/7 Started on Wednesday, January 17, 2024, 3:43 PM State Finished Completed on Wednesday, January 17, 2024, 3:54 PM Time taken 10 mins 34 secs Points 4.17/10.00 Grade 41.67 out of 100.00 Question 1 Incorrect 0.00 points out of 1.00 For the histogram shown below, select the correct order for the measures of center. Right Skewed Histogram: Explained with Examples - All Things Statistics a. The mode is the smallest, then the median, then the mean. b. The mean is the smallest, then the mode, then the median. c. The mode is the smallest, then the mean, then the median.  d. The mean is the smallest, then the median, then the mode. e. The median is the smallest, then the mode, then the mean. f. The median is the smallest, then the mean, then the mode. Your answer is incorrect. The correct answer is: The mode is the smallest, then the median, then the mean.

3/28/24, 1:09 PM Quiz 2: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1453498&cmid=955444 2/7 Question 2 Partially correct 0.17 points out of 1.00 Levels of endotoxin in the blood serum of pregnant women is recorded for two groups in a research study: the Main group and the Control group. The boxplots below display this data. Select all of the following statements which are true . a. All endotoxin levels in the Main group are higher than all endotoxin levels in the Control group. b. The Main group's endotoxin levels have less variability than the Control group's.  c. The typical endotoxin level for the Main group is higher than that of the Control group.  d. The distribution of endotoxin level for the Control group appears to be symmetric and unimodal. e. The Control group has a similar IQR to the Main group. Your answer is partially correct. You have correctly selected 1. The correct answers are: The typical endotoxin level for the Main group is higher than that of the Control group., The Control group has a similar IQR to the Main group.

3/28/24, 1:09 PM Quiz 2: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1453498&cmid=955444 3/7 Question 3 Correct 1.00 points out of 1.00 Question 4 Correct 1.00 points out of 1.00 A sleep pod is similar to a sleeping bag but delivers light pressure to your body. The effect of using a sleep pod to reduce anxiety is being studied. Fifty patients with documented anxiety agree to participate in a study. Half of these patients are randomly assigned to use the sleep pod each night. The other half do not use a sleep pod. In the study above, can the placebo effect be separated from the treatment effect? a. No - the treatment group can still experience the placebo effect, so we cannot determine the effect of the treatment.  b. No - when only one group receives a placebo, only that group experiences the placebo effect. c. Yes - because each group receives some form of "treatment" (fake or not), each group may experience the placebo effect. d. Yes - because only one group received the placebo. Your answer is correct. The correct answer is: No - the treatment group can still experience the placebo effect, so we cannot determine the effect of the treatment. True or False: The heights of Softball Players have a larger standard deviation than Basketball Players. True False  The correct answer is 'False'.

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3/28/24, 1:09 PM Quiz 2: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1453498&cmid=955444 4/7 Question 5 Incorrect 0.00 points out of 1.00 Question 6 Incorrect 0.00 points out of 1.00 For the histogram shown below, which measure of variability is most reliable/appropriate? Right Skewed Histogram: Explained with Examples - All Things Statistics a. Standard deviation, since there are no outliers. b. Standard deviation, since it uses all of the data.  c. IQR, since the data is quantitative and discrete. d. We do not have enough information about this data to know which is more appropriate. e. IQR, since the distribution is skewed. Your answer is incorrect. The correct answer is: IQR, since the distribution is skewed. Recently, a group of adults who swim regularly for exercise were evaluated for depression. It turned out that these swimmers were less likely to be depressed than the general population, a result that the study found to be significant. Based on this outcome, select all of the following statements which are true. a. Because the result was significant, this proves that swimming prevents depression b. A lurking variable may be responsible for the low levels of depression in these swimmers.  c. Any exercise can prevent depression, not just swimming  d. These swimmers were not assigned to this exercise, so we do not know if swimming prevents depression. Your answer is incorrect. The correct answers are: A lurking variable may be responsible for the low levels of depression in these swimmers., These swimmers were not assigned to this exercise, so we do not know if swimming prevents depression.

3/28/24, 1:09 PM Quiz 2: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1453498&cmid=955444 5/7 Question 7 Incorrect 0.00 points out of 1.00 Math scores for students in a particular grade are recorded. Here is a histogram of the scores: Which would you report: the mean or the median? a. The mean - Since the distribution is skewed left, the mean is less than the median and smaller values are better measures of center. b. The median - Since the distribution is skewed left, the median is a better measure of center because it will not include those values in the skew. c. The mean - Since the distribution is skewed left, the mean is a better measure of center because it will include those values in the skew. d. The mean - Since there are only a few values on the left, the mean will not be influenced much. Since the mean is preferable to the median, it is still ok to use here.  e. The median - Since the data is quantitative, the mean is not a good choice. Your answer is incorrect. The correct answer is: The median - Since the distribution is skewed left, the median is a better measure of center because it will not include those values in the skew.

3/28/24, 1:09 PM Quiz 2: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1453498&cmid=955444 6/7 Question 8 Correct 1.00 points out of 1.00 Question 9 Correct 1.00 points out of 1.00 Scientists at a major pharmaceutical firm investigated the effectiveness of an herbal compound to treat the common cold. They randomly selected 50 adults and exposed each subject to a cold virus, then gave him or her either the herbal compound or a sugar solution known to have no effect on colds. Several days later, they assessed the patient’s condition, using a cold severity scale ranging from 0 to 5. They found no evidence of benefits associated with the compound. Match each of the following below. Population of Interest  Explanatory variable  Response variable  Subjects  Adults exposed to cold virus Herbal compound or Sugar solution Severity of cold symptoms The 50 adults in the study Your answer is correct. The correct answer is: Population of Interest → Adults exposed to cold virus Explanatory variable → Herbal compound or Sugar solution Response variable → Severity of cold symptoms Subjects → The 50 adults in the study For each scenario given below, identify the method of data collection is most appropriate. A study aims to answer the question, "What is the average amount that Amazon.com shoppers spend during November?"  A researcher wants to know what effect a daily dose of ibuprofen has on the lining of the stomach.  Observational Study Experiment Your answer is correct. The correct answer is: A study aims to answer the question, "What is the average amount that Amazon.com shoppers spend during November?" → Observational Study A researcher wants to know what effect a daily dose of ibuprofen has on the lining of the stomach. → Experiment

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3/28/24, 1:09 PM Quiz 2: Attempt review | Courses 2023-2024 https://moodle-courses2324.wolfware.ncsu.edu/mod/quiz/review.php?attempt=1453498&cmid=955444 7/7 Question 10 Incorrect 0.00 points out of 1.00 A group of psychiatric researchers are designing a study to determine if a newly developed antipsychotic medicine is an effective treatment for patients with bipolar disorder. The researchers obtain a sample of 100 patients who have bipolar disorder, consisting of 44 men and 56 women. They assign each a number from 1 to 100. Using a random number generator, they select 50 patients to receive the new medicine, and the other 50 patients take a placebo. What study design (randomization method) was used here? a. Matched Pairs Design b. Other c. Randomized Block Design  d. Completely Randomized Design Your answer is incorrect. The correct answer is: Completely Randomized Design ◄ ICA 2 Jump to... Week 2 Review Slides ►