STATS UNIT 2

use scenario 4-4: another correct choice of labels for the 816 students is

400, 769, 335

use eight student scenario: choose a simple random sample

Alvarez, Barlow, Salter, and Verducci

use list of names scenario: the simple random sample is

Bechhofer, Taylor, Weiss

use scenario 4-4: another correct choice of labels for the 816

Both (B) and (C) are correct

cholesterol scenario: which of the following best describes the inferences the researcher can make based in his results

He can make inferences about the populations from which the samples were taken, but not cause and effect

use list of names scenario: which of these statements about the tale of random digits is true

None of these are true

a poll conducted by the student newspaper asked, "who do you believe will win the Ohio State..."

The results of the survey are unreliable because response to the survey was voluntary

Use Lafayette scenario: the newspaper asks you to comment on their survey

This is a convenience sample. It will almost certainly overestimate the level of support among all Lafayette residents

In order to assess the opinion of students at the University of Minnesota, snow removal

a convenience sample

a simple random sample is

a sample that gives every possible sample of the same size the same chance to be selected

a lurking variable is

a variable that is not among the variables studied but that affects the response variable

when controlled experiments are impractical or unethical

all of the above

Lafayette residents, first 20 people

all residents of Lafayette

A news release for a diet products company reports:

biased, overstating the effectiveness of the diet

a study sponsored by American Express Co

biased, overstating the extent to which the old stereotypes

which of the following statements about randomized block design

block a is chosen randomly from among the available experimental units

caffeine performance scenario: randomly allocated

block design

which of the following is not a major principle of good design for all experimets

blocking

To determine the proportion of each color of Peanut Butter M&M, you buy 10 1.69 ounce packages and count

cluster sampling

a marine biologist wants to estimate the mean size of the barnacle in Semibalanus

cluster sampling

if changes in a response variable are due to the effects of the explanatory variable as well as the effects of

confounding

use caffeine performance example: unfortunately, any difference could be due to the two sessions having different teachers

confounding

the principle reason for the use of random assignment in designing experiments is that it

creates apporx. equal groups for comparison

the principle reason for the use of controls in designing experiments is that it

distinguishes a treatment effect from the effects of confounding variables

cholesterol scenario: this is a(n)

double blind experiment

double blind experiment was conducted to evaulate effectiveness of polio vaccine

eliminate possible source of bias

caffeine performance scenario: the response variable is

exam performance

the most important advantage of experiments over observational studies is that

experiments can give better evidence of causation

heart rate and steps

factors

use list of names scenario: which of the following statements is true

if we use another list of random digits to select the sample, the result obtained with the list actually used would be just as likely to be selected as any other set of three names

an example of a non-sampling error that can reduce the accuracy

many members of the sample cannot by contacted

spaghetti sauce

matched pairs

dogs disks (black and red)

matched pairs design

kindergarten class

may be confounding variables in this study

an opinion research firm wants to find the country's reaction by a famous politician

multistage sampling

simple random sampling

none of the above

frequently, telephone poll-takers call near dinner time - between 6 pm and 7 pm -

nonresponse

the essential difference between an experiment and an observational study is

observational studies are always biased

caffeine performance example: coffee taste bad

placebo effect

blocking is used sometimes to

reduce variability from arising in random assignment

principle reason for replication

reduces sampling variability

The Bradley effect is a theory proposed to explain observed discrepancies between voter opinion polls and election outcomes in some elections

response bias

in an experiment, an observed effect so large that it would rarely occur by chance is called

statistically significant

A public opinion poll in Ohio wants to determine whether or not registered voters in the state approve of a measure

stratified random sample

we divide the class into two groups: first-year students and others. We then take random samples from each group

stratified random sampling

you plan to give a math achievement test to samples of 15 year olds from both the US and Korea in order to compare

stratified random sampling

Medical researchers are excited about a new cancer treatment that destroys tumors by cutting off their blood supply

suffers from realism

medication scenario: the experimental units are

the 100 volunteers

Use Lafayette example: The sample for the survey is

the 20 people who gave the sportswriter their opinion

in comparative trials in medicine the placebo effect can be avoided

the double blind technique

a stratified random sample is appropriate when

the population can be easily subdivided into groups according to some categorical variable, and the variable you are

a 1992 roper poll found that 22% of Americans say that the holocaust

the question is worded in a confusing manner

A marketing research firm wishes to determine if the adult men in Laramie

the same as for any other set of 100 residential addresses

medication scenario: which describes inferences that can be made

they can make inferences about cause and effect, but not about population from which samples were taken

Just before the presidential elction of 1936 the magazine Literary digest

undercoverage

a local tax reform group polls the residents of the school district

underestimate support for arts programs because of nonsampling error

a television station is interested in predicting whether voters in its viewing area in favor

voluntary response sample

twelve people who suffer from chronic fatigue

we believe men and women will react differently

A market research company wishes to find out whether the population of students at a university prefers brand A or brand B of coffee. Response variable?

which brand they prefer

100 volunteers suffer from depression

which treatment volunteers recieve