Quiz 4 Retake Flashcards
(9 cards)
A study was done to compare the lung capacity of coal miners to the lung capacity of farm workers. The researcher studied 200 workers of each type. There are other factors that might affect lung capacity that could explain the association, smoking habits and exercise habits. The smoking habits of the two worker types are similar, but the coal miners generally exercise less than the farm workers.
Which of the following is the explanatory variable in this study?
Occupation
Exercise
Smoking or not
Lung capacity
Occupation
January 22, 2016, NPR news headline reads “Why Poverty May Be More Relevant Than Race For Childhood Obesity.” The study collected data on a random sample of K-12 students in Massachusetts. The article states, “At first glance, it looked like childhood obesity was more common among African Americans or Hispanics…” After which they looked at poverty as a possible _________________.
Quantitative variable.
Normal variable.
Confounding variable.
Response variable.
Confounding variable.
An experiment was done by randomly assigning each participant to walk for half an hour three times a week or sit quietly reading a book for half an hour three times a week. At the end of a year the change in participants’ blood pressure over the year was measured, and the change was compared for the two groups.
This is an experiment rather than an observational study because:
A random sample of participants was used.
The participants were randomly assigned to either walk or read, rather than choosing their own activity.
Blood pressure was measured at the beginning and end of the study.
The two groups were compared at the end of the study.
The participants were randomly assigned to either walk or read, rather than choosing their own activity.
In a study on treatments for anorexia, researchers recruited 30 teenage girls with anorexia. The girls were ranked by weight prior to the study. Of the heaviest three girls, one was randomly assigned to a “family” therapy, one to a “cognitive/behavioral” therapy, and one to a control group. The same was done for the next three heaviest girls, down to the three lightest girls. After five weeks of treatment, researchers weighed the participants. Researchers would like to determine which, if any, of the treatments are most effective in treating anorexia.
Can the results from this study be generalized to the population of all teenage girls with anorexia?
No, since it is an observational study.
Yes, since it is a randomized experiment.
No, since the participants in the study were volunteers.
Yes, since the treatments were randomly assigned.
No, since the participants in the study were volunteers.
Whirling disease is a deadly disease that affects trout in Montana rivers. In a follow-up to a 2006 study conducted by the Montana Department of Fish, Wildlife and Parks (FWP), researchers sought to determine if the proportion of trout afflicted by whirling disease in the Gallatin river differs between rainbow trout and brown trout.
To test this theory, researchers collected a representative sample of 527 rainbow trout and 459 brown trout. Of the 527 rainbow trout collected, 120 had developed whirling disease; of the 459 brown trout collected, 74 had developed whirling disease.
Given that rainbow trout have a 0.228 conditional probability of developing whirling disease and brown trout have a 0.161 conditional probability, does it appear that whether a trout develops whirling disease is associated with the species of trout (rainbow or brown)?
No, since there were approximately the same number of trout in each species.
Yes, since the proportion of trout that developed the disease was not equal to 0.5.
Yes, since the conditional proportion of trout that developed the disease differed between rainbow and brown trout.
Yes, since the number of trout who developed whirling disease differed from the number of trout who did not develop whirling disease.
Yes, since the proportion of trout that developed the disease was not equal to 0.5.
Whirling disease is a deadly disease that affects trout in Montana rivers. In a follow-up to a 2006 study conducted by the Montana Department of Fish, Wildlife and Parks (FWP), researchers sought to determine if the proportion of trout afflicted by whirling disease in the Gallatin river differs between rainbow trout and brown trout.
To test this theory, researchers collected a representative sample of 527 rainbow trout and 459 brown trout. Of the 527 rainbow trout collected, 120 had developed whirling disease; of the 459 brown trout collected, 74 had developed whirling disease.
Which of the following plots would be most appropriate to examine the association between the explanatory and response variables?
Histogram
Mosaic plot
Segmented bar chart or mosaic plot
Segmented bar chart
Segmented bar chart or mosaic plot
A Gallup poll headline from April 25, 2013, reads “In U.S., Women Veterans Rate Lives Better Than Men”. In a random sample of 900 female veterans interviewed, 459 rated their lives as “thriving.” Only 693 male veterans rated their lives as “thriving” in a random sample of size 1,650.
What is the alternative hypothesis if researchers are interested in determining if the long-run proportion who would rate their lives as thriving differs between women and men?
There is no association between sex and whether a veteran would rate their life as thriving.
There is an association between sex and whether a veteran would rate their life as thriving.
There is an association between whether a person is a veteran and whether a person would rate their life as thriving.
There is no association between whether a person is a veteran and whether a person would rate their life as thriving.
There is an association between sex and whether a veteran would rate their life as thriving.
A 2003 study examined how well consumers protect themselves from identity theft. The study surveyed a random sample of 61 college students and 59 non-students, and asked each participant, “Have you used personal information (such as birth date, pet name, etc.) when creating a password?”
For the students, 22 agreed with this statement, while 30 of the non-students agreed.
Is a theory-based approach appropriate to test
H0: πstudent - πnon-student = 0 versus Ha: πstudent - πnon-student ≠ 0?
Yes, since 22, 30, 39, and 29 are all larger than 10.
Yes, since 120 is larger than 20.
No, since a simulation-based approach is always appropriate.
Yes, since 61 and 59 are both greater than 20.
Yes, since 22, 30, 39, and 29 are all larger than 10.
A 2003 study examined how well consumers protect themselves from identity theft. The study surveyed a random sample of 61 college students and 59 non-students, and asked each participant, “Have you used personal information (such as birth date, pet name, etc.) when creating a password?”
For the students, 22 agreed with this statement, while 30 of the non-students agreed.
Use the Theory-Based Inference applet to find the p-value for a test of hypothesis
H0 : πstudent - πnon-student = 0 versus Ha : πstudent - πnon-student ≠ 0?
0.9488
0.0512
0.1023
0.1480
0.1023
