StatTutor Lesson - Randomized Comparative Experiments

true
Stat Tutor
true
true
You have completed 0 question sequences out of 12.
Current Time 0:00
Duration 0:00
Loaded: 0%
Stream Type LIVE
Remaining Time 0:00
 
1x
    • Chapters
    • descriptions off, selected
    • captions off, selected

      Questions 1-2

      47

      Question 1.

      Which of the following is NOT a principle of a good experiment?

      		A.
      		B.
      		C.
      		D.
      Incorrect. Confounding is usually not a desired principle of a good experiment.
      Correct. Confounding is usually not a desired principle of a good experiment.
      Incorrect. Try again.
      2

      Questions 3-4

      112

      Question 3.

      Why is a control necessary?

      		A.
      		B.
      		C.
      Incorrect. Without a control and randomization, a researcher will not know if the treatment worked or if a lurking variable affected the response variable.
      Correct. Without a control and randomization, a researcher will not know if the treatment worked or if a lurking variable affected the response variable.
      Incorrect. Try again.
      2

      Question 5

      144

      Question 5.

      What is randomization in an experiment?

      		A.
      		B.
      		C.
      Incorrect. Randomization in an experiment is using chance to assign subjects to treatments
      Correct. Randomization in an experiment is using chance to assign subjects to treatments
      Incorrect. Try again.
      2

      Question 6

      162

      Question 6.

      What is replication in an experiment?

      		A.
      		B.
      		C.
      Incorrect. In order to measure variation, we must have at least two individuals receive each treatment. Repeating the entire experiment is NOT what is meant by replication in an experiment.
      Correct. In order to measure variation, we must have at least two individuals receive each treatment. Repeating the entire experiment is NOT what is meant by replication in an experiment.
      Incorrect. Try again.
      2

      Questions 7-8

      230

      Question 7.

      Which of the following gives evidence of a cause and effect relationship between the explanatory and response variables?

      		A.
      		B.
      Incorrect. A well-designed survey does not provide evidence of cause and effect due to potential lurking variables.
      Correct. A well-designed survey does not provide evidence of cause and effect due to potential lurking variables.
      Incorrect. Try again.
      2

      Questions 9-10

      294

      Question 9.

      Which of the following is a possible consequence of not having randomization in a study?

      		A.
      		B.
      		C.
      		D.
      		E.
      Incorrect. All of the above are problems that could result from not having randomization in a study.
      Correct. All of the above are problems that could result from not having randomization in a study.
      Incorrect. Try again.
      2

      Questions 11-12

      345

      Question 11.

      Which principle of experimentation is lacking in observational studies?

      		A.
      		B.
      		C.
      Incorrect. Observational studies usually have control/comparison and replication; they lack random assignment of subjects to treatments.
      Correct. Observational studies usually have control/comparison and replication; they lack random assignment of subjects to treatments.
      Incorrect. Try again.
      2

      Questions 13-15

      442

      Question 13.

      Does this study have control/comparison?

      		A.
      		B.
      Incorrect. Because a new diet is compared with a standard diet, there is control/comparison.
      Correct. Because a new diet is compared with a standard diet, there is control/comparison.
      Incorrect. Try again.
      2

      Question 16

      484

      Question 16.

      How were the rats assigned to each group?

      		A.
      		B.
      		C.
      Incorrect. Valid randomization requires that a random device be used to assign rats to treatments. In this case, a random digit table was used to select 15 rats.
      Correct. Valid randomization requires that a random device be used to assign rats to treatments. In this case, a random digit table was used to select 15 rats.
      Incorrect. Try again.
      2

      Questions 17-18

      523

      Question 17.

      What was measured on each rat? i.e., what is the response variable?

      		A.
      		B.
      		C.
      Incorrect. Weight gain was measured on each rat, so that is the response variable. "Mean weight gain" is an aggregate measure on 15 rats, not on each rat, so it is not the response variable.
      Correct. Weight gain was measured on each rat, so that is the response variable. "Mean weight gain" is an aggregate measure on 15 rats, not on each rat, so it is not the response variable.
      Incorrect. Try again.
      2

      Question 19

      530

      Question 19.

      Why is testing for statistical significance valid for this experiment?

      		A.
      		B.
      		C.
      		D.
      Incorrect. Most importantly, this study incorporates random assignment of rats to type of diet.
      Correct. Most importantly, this study incorporates random assignment of rats to type of diet.
      Incorrect. Try again.
      2

      Question 20

      566

      Question 20.

      True or false: All three principles are always required for a valid experiment.

      		A.
      		B.
      Incorrect. This is a correct statement.
      Correct. This is a correct statement.
      Incorrect. Try again.
      2