Unit 4

Question 1

The entire group of individuals we want information about

Answer 1

Population

Question 2

Collects data from every individual in the population

Answer 2

Census

Question 3

A subset of individuals in the population from which we collect data

Answer 3

Sample

Question 4

A study that collects data from a sample to learn about the population from which the sample was selected

Answer 4

Sample Survey

Question 5

Selects individuals from the population who are easy to reach

Answer 5

Convenience Sampling

Question 6

A study shows this if it is very likely to underestimate or very likely to overestimate the value you want to know

Answer 6

Bias

Question 7

Allows people to choose to be in the sample by responding to a general invitation

Answer 7

Voluntary Response Sampling

Question 8

Involves using a chance process to determine which members of a population are included in the sample

Answer 8

Random Sampling

Question 9

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

Answer 9

Simple Random Sample (SRS)

Question 10

An individual from a population can be selected only once

Answer 10

Sampling Without Replacement

Question 11

An individual from a population can be selected more than once

Answer 11

Sampling With Replacement

Question 12

Groups of individuals in a population who share characteristics thought to be associated with the variables being measured in a study

Answer 12

Strata

Question 13

Selects a sample by choosing an SRS from each stratum and combining the SRSs into one overall sample

Answer 13

Stratified Random Sampling

Question 14

A group of individuals in a population that are located near each other

Answer 14

Cluster

Question 15

Selects a sample by randomly choosing clusters and including each member of the selected clusters in the sample

Answer 15

Cluster Sampling

Question 16

Selects a sample from an ordered arrangement of the population by randomly selecting one of the first k individuals and choosing every kth individual thereafter

Answer 16

Systematic Random Sampling

Question 17

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

Answer 17

Undercoverage

Question 18

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

Answer 18

Nonresponse

Question 19

Occurs when there is a systematic pattern of inaccurate answers to a survey question

Answer 19

Response Bias

Question 20

Observes individuals and measures variables of interest but does not attempt to influence the responses

Answer 20

Observational Study

Question 21

Measures the outcome of a study

Answer 21

Response Variable

Question 22

May help explain or predict changes in a response variable

Answer 22

Explanatory Variable

Question 23

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

Answer 23

Confounding

Question 24

Deliberately imposes treatments on individuals to measure their responses

Answer 24

Experiment

Question 25

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

Answer 25

Placebo

Question 26

A specific condition applied to the individuals in an experiment

Answer 26

Treatment

Question 27

The object to which a treatment is randomly assigned

Answer 27

Experimental Unit

Question 28

Term given to experimental units that are human beings

Answer 28

Subjects

Question 29

An explanatory variable that is manipulated and may cause a change in the response variable

Answer 29

Factor

Question 30

Different values of a factor

Answer 30

Levels

Question 31

Used to provide a baseline for comparing the effects of other treatments

Answer 31

Control Group

Question 32

Describes the fact that some subjects in an experiment will respond favorably to any treatment, even an inactive treatment

Answer 32

Placebo Effect

Question 33

Neither the subjects nor those who interact with them and measure the response variable know which treatment a subject is receiving

Answer 33

Double-Blind

Question 34

Either the subjects or the people who interact with them and measure the response variable don't know which treatment a subject is receiving

Answer 34

Single-Blind

Question 35

Experimental units are assigned to treatments using a chance process

Answer 35

Random Assignment

Question 36

Keeping other variables constant for all experimental units

Answer 36

Control

Question 37

Giving each treatment to enough experimental units so that a difference in the effects of the treatments can be distinguished from chance variation due to the random assignment

Answer 37

Replication

Question 38

The experimental units are assigned to the treatments completely at random

Answer 38

Completely Randomized Design

Question 39

A 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

Answer 39

Block

Question 40

The random assignment of experimental units to treatments is carried out within each block

Answer 40

Randomized Block Design

Question 41

A common experimental design for comparing two treatments that uses blocks of size 2

Answer 41

Matched Pairs Design

Question 42

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

Answer 42

Sampling Variability

Question 43

When the observed results of a study are too unusual to be explained by chance alone

Answer 43

Statistically Significant