4

Question 1

census

Answer 1

Study that attempts to collect data from every individual in the population. (p. 221)

Question 2

sample

Answer 2

Subset of individuals in the population from which we collect data. (p. 221)

Question 3

population

Answer 3

In a statistical study, the entire group of individuals we want information about

Question 4

sample survey

Answer 4

Study that uses an organized plan to choose a sample that represents some specific population. We base conclusions about the population on data from the sample.

Question 5

convenience sampling

Answer 5

Sample selected by taking from the population individuals that are easy to reach

Question 6

voluntary response sampling

Answer 6

A sample that consists of people who choose to be in the sample by responding to a general invitation. Voluntary response samples are sometimes called self-selected samples.

Question 7

The design of a statistical study shows bias if

Answer 7

it is very likely to underestimate or very likely to overestimate the value you want to know

Question 8

random sampling

Answer 8

Using a chance process to determine which members of a population are chosen for the sample.

Question 9

simple random sample

Answer 9

Sample chosen in such a way that every group of n individuals in the population has an equal chance to be selected as the sample

Question 10

stratified random sampling

Answer 10

Sample obtained by classifying the population into groups of similar individuals, called strata, then choosing a separate SRS in each stratum and combining these SRSs to form the sample

Question 11

cluster sampling

Answer 11

Sample obtained by classifying the population into groups of individuals that are located near each other, called clusters, and then choosing an SRS of the clusters

Question 12

undercoverage

Answer 12

Occurs when some members of the population are less likely to be chosen or cannot be chosen in a sample

Question 13

nonresponse

Answer 13

Occurs when an individual chosen for the sample can’t be contacted or refuses to participate.

Question 14

wording of questions

Answer 14

An important influence on the answers given in a survey. Confusing or leading questions can introduce strong bias, and changes in wording can greatly change a survey’s outcome

Question 15

response bias

Answer 15

Occurs when there is a consistent pattern of inaccurate responses to a survey question

Question 16

observational study

Answer 16

Study that observes individuals and measures variables of interest but does not attempt to influence the responses

Question 17

confounding

Answer 17

When two variables are associated in such a way that their effects on a response variable cannot be distinguished from each other

Question 18

experiments

Answer 18

A study in which researchers deliberately impose treatments on individuals to measure their responses.

Question 19

placebo

Answer 19

A treatment that has no active ingredient but is otherwise like other treatments

Question 20

treatment

Answer 20

Specific condition applied to the individuals in an experiment. If an experiment has several explanatory variables, a treatment is a combination of specific values of these variables

Question 21

experimental unit

Answer 21

The object to which a treatment is randomly assigned. When the experimental units are human beings, they are often called subjects.

Question 22

subjects

Answer 22

Experimental units that are human beings.

Question 23

factor

Answer 23

Explanatory variable in an experiment

Question 24

level

Answer 24

Specific value of an explanatory variable (factor) in an experiment

Question 25

comparison

Answer 25

Experimental design principle. Use a design that compares two or more treatments.

Question 26

control group

Answer 26

Experimental group whose primary purpose is to provide a baseline for comparing the effects of the other treatments.

Question 27

placebo effect

Answer 27

Describes the fact that some subjects respond favorably to any treatment, even an inactive one (placebo).

Question 28

double-blind

Answer 28

An experiment in which neither the subjects nor those who interact with them and measure the response variable know which treatment a subject received

Question 29

single-blind

Answer 29

An experiment in which either the subjects or those who interact with them and measure the response variable, but not both, know which treatment a subject received

Question 30

random assignment

Answer 30

Experimental design principle. Use chance to assign experimental units to treatments

Question 31

control

Answer 31

Experimental design principle that mandates keeping other variables that might affect the response the same for all experimental units

Question 32

replication

Answer 32

Experimental design principle

Question 33

completely randomized design

Answer 33

Design in which the experimental units are assigned to the treatments completely by chance

Question 34

block

Answer 34

Group of experimental units that are known before the experiment to be similar in some way that is expected to affect the response to the treatments

Question 35

randomized block design

Answer 35

Experimental design begun by forming blocks consisting of individuals that are similar in some way that is important to the response.

Question 36

matched pairs design

Answer 36

Common form of blocking for comparing just two treatments

Question 37

sampling variability

Answer 37

The fact that different random samples of the same size from the same population produce different estimates

Question 38

nference

Answer 38

Drawing conclusions that go beyond the data at hand.

Question 39

margin of error

Answer 39

The difference between the point estimate and the true parameter value will be less than the margin of error in C% of all samples, where C is the confidence level

Question 40

statistically significant

Answer 40

When the observed results of a study are too unusual to be explained by chance alone, the results are called statistically significant.`

Question 41

anonymity

Answer 41

The names of individuals participating in a study are not known even to the director of the study

Question 42

confidential

Answer 42

A basic principle of data ethics that requires that an individual’s data be kept private

Question 43

informed consent

Answer 43

Basic principle of data ethics that states that individuals must be informed in advance about the nature of a study and any risk of harm it may bring.

Question 44

institutional review board

Answer 44

Board charged with protecting the safety and well-being of the participants in advance of a planned study and with monitoring the study itself.

Question 45

inference about cause and effect

Answer 45

Conclusion from the results of an experiment that the treatments caused the difference in responses

Question 46

inference about a population

Answer 46

Conclusion about the larger population based on sample data. Requires that the individuals taking part in a study be randomly selected from the population of interest.