14 to prevent bias experimenters try to assign

Info iconThis preview shows pages 12–15. Sign up to view the full content.

View Full Document Right Arrow Icon
14. To prevent bias, experimenters try to assign subjects to a group so that neither the subjects nor the people who evaluate them know which treatment group the subject is in. An experiment of this type is described as ________________________. 15. Doctors investigated the relationship between a person’s heart rate and the frequency at which that person stepped up and down on steps of various heights. There were 3 rates of stepping and 2 different step heights used. A subject performed the activity (stepping at one of the 3 stepping rates at one of the 2 possible heights) for three minutes. His heart rate was then measured. (a) State what the factors are in this experiment. Next to each factor state its number of levels. (b) How many treatments are in this experiment? _____________ (c) Identify one of the treatments. _____________________________ (d) What is the response variable for this study? ________________
Background image of page 12

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chapter 5: Producing Data Names of 12 subjects are listed followed by a line of random digits. Ahbel Barnes Calhoun Dancer Freda Keller Magee Marge McCullion Stevens Meier Winokur 41842 81068 09001 03367 49497 54580 81507 27102 56027 55892 33063 71035 e) Demonstrate your understanding of simple random sampling by using the random digits to determine which subjects would be randomly assigned to the first treatment. List these names: ___________________________________________________________________________ f) Describe how your selections were made. Be sufficiently clear in your description that I can duplicate your work. g) Demonstrate your understanding of random blocked sampling by using the random digits to determine which subjects would be randomly assigned to the first treatment. List these names: ___________________________________________________ h) Describe how your selections were made. Be sufficiently clear in your description that I can duplicate your work. 16. A 1994 article in Science magazine discussed a study comparing the health of 6000 vegetarians and a similar number of people who were not vegetarians. The vegetarians had a 28% lower death rate from heart attacks. (a) Is this an observational study or an experiment? _____________________________________ (b) Give an example of a potential confounding variable and explain what it means to say that this is a confounding variable. (c) Give an example of an extraneous variable that you would not expect to be a confounding variable. Explain why you think this variable would not be confounding. Homework: pg 380-3 problems 5.61-3, 66, 68, 70-72
Background image of page 13
Chapter 5: Producing Data From the AP Stats Listserv a response from one of the “fathers” of AP Statistics: Chris and Peter, I have always liked the way George Cobb presents this idea in experimental design. In Introduction to the Design and Analysis of Experiments, George Cobb (1998) describes the variability inherent an
Background image of page 14

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 15
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page12 / 16

14 To prevent bias experimenters try to assign subjects to...

This preview shows document pages 12 - 15. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online