Sampling and Experiments

Question 1

sample

Answer 1

a representative subset of a population

Question 2

population

Answer 2

the entire group of individuals which about whom we intend to learn

Question 3

bias

Answer 3

a SYSTEMATIC failure of a sample to represent a population

Question 4

voluntary response bias

Answer 4

bias from individuals who choose to not be in the sample

Question 5

nonresponse bias

Answer 5

bias from individuals in the sample who fail to respond

Question 6

convenience sample

Answer 6

a sample of individuals who are easy to survey; this sample typically is biased

Question 7

undercoverage

Answer 7

this results from any sampling method that under-represents a segment of a population

Question 8

response bias

Answer 8

anything in a survey that causes subjects to respond differently from the truth

Question 9

systematic random sample

Answer 9

Example: randomly survey every 12th person in line at a movie theater

Question 10

cluster sample

Answer 10

a random sample of several diverse groups (and each group is representative of the population)

Question 11

stratified sample

Answer 11

a random sample taken from each of several homogenous (alike in some way) groups

Question 12

sampling frame

Answer 12

the “list” from which a random sample may be drawn (it may not be a real list)

Question 13

sampling variability

Answer 13

the variability that naturally occurs from sample to sample

Question 14

simple random sample (SRS)

Answer 14

a random sampling method where each subset of the population has an equal chance of being selected

Question 15

statistic

Answer 15

a calculation from a sample

Question 16

parameter

Answer 16

a numerical characteristic from a population

Question 17

census

Answer 17

a survey that contains the entire population

Question 18

strata

Answer 18

a group of individuals that are alike in some important way

Question 19

cluster

Answer 19

a group of individuals that are very diverse, and who represent the population well

Question 20

multistage sanple

Answer 20

a sampling method that combines several sampling methods to obtain a sample from a population

Question 21

observational study

Answer 21

a study in which no treatments are assigned to subjects; they are simple observed

Question 22

retrospective study

Answer 22

a study in which data from the past is collected on subjects for analysis

Question 23

prospective study

Answer 23

a study in which subjects are followed and data is collected in the future

Question 24

experiment

Answer 24

a study in which treatments are assigned to subjects and responses are analyzed

Question 25

factor

Answer 25

a variable whose levels are set by an experimenter (to see if there is an effect on the response variable of interest)

Question 26

level

Answer 26

the value that an experimenter chooses for a factor

Question 27

experimental units (subjects)

Answer 27

the individuals on which an experiment is performed

Question 28

treatment

Answer 28

the different levels of a factor

Question 29

three principles of good experimental design

Answer 29

control, randomization, replication

Question 30

control group

Answer 30

a treatment group that gets no treatment (or a placebo)

Question 31

blinding

Answer 31

when an individual does not know which treatment is given to a subject

Question 32

double blind

Answer 32

when neither the subjects nor the evaluators know which treatment is given to subjects

Question 33

placebo

Answer 33

a treatment that is know to have no effect

Question 34

blocking

Answer 34

a design where an experiment is conducted in each of several groups that are alike in some important way (Example: groupings by gender, by age, by race, etc.)

Question 35

confounding

Answer 35

this happens when the levels of one variable are hopelessly mixed together with the levels of another variable (making it impossible to determine which levels are truly affecting the response variable of interest)

Question 36

a representative subset of a population

Answer 36

sample

Question 37

the entire group of individuals which about whom we intend to learn

Answer 37

population

Question 38

a SYSTEMATIC failure of a sample to represent a population

Answer 38

bias

Question 39

bias from individuals who choose to not be in the sample

Answer 39

voluntary response bias

Question 40

bias from individuals in the sample who fail to respond

Answer 40

nonresponse bias

Question 41

a sample of individuals who are easy to survey; this sample typically is biased

Answer 41

convenience sample

Question 42

this results from any sampling method that under-represents a segment of a population

Answer 42

undercoverage

Question 43

anything in a survey that causes subjects to respond differently from the truth

Answer 43

response bias

Question 44

Example: randomly survey every 12th person in line at a movie theater

Answer 44

systematic random sample

Question 45

a random sample of several diverse groups (and each group is representative of the population)

Answer 45

cluster sample

Question 46

a random sample taken from each of several homogenous (alike in some way) groups

Answer 46

stratified sample

Question 47

the “list” from which a random sample may be drawn (it may not be a real list)

Answer 47

sampling frame

Question 48

the variability that naturally occurs from sample to sample

Answer 48

sampling variability

Question 49

a random sampling method where each subset of the population has an equal chance of being selected

Answer 49

simple random sample (SRS)

Question 50

a calculation from a sample

Answer 50

statistic

Question 51

a numerical characteristic from a population

Answer 51

parameter

Question 52

a survey that contains the entire population

Answer 52

census

Question 53

a group of individuals that are alike in some important way

Answer 53

strata

Question 54

a group of individuals that are very diverse, and who represent the population well

Answer 54

cluster

Question 55

a sampling method that combines several sampling methods to obtain a sample from a population

Answer 55

multistage sanple

Question 56

a study in which no treatments are assigned to subjects; they are simple observed

Answer 56

observational study

Question 57

a study in which data from the past is collected on subjects for analysis

Answer 57

retrospective study

Question 58

a study in which subjects are followed and data is collected in the future

Answer 58

prospective study

Question 59

a study in which treatments are assigned to subjects and responses are analyzed

Answer 59

experiment

Question 60

a variable whose levels are set by an experimenter (to see if there is an effect on the response variable of interest)

Answer 60

factor

Question 61

the value that an experimenter chooses for a factor

Answer 61

level

Question 62

the individuals on which an experiment is performed

Answer 62

experimental units (subjects)

Question 63

the different levels of a factor

Answer 63

treatment

Question 64

control, randomization, replication

Answer 64

three principles of good experimental design

Question 65

a treatment group that gets no treatment (or a placebo)

Answer 65

control group

Question 66

when an individual does not know which treatment is given to a subject

Answer 66

blinding

Question 67

when neither the subjects nor the evaluators know which treatment is given to subjects

Answer 67

double blind

Question 68

a treatment that is know to have no effect

Answer 68

placebo

Question 69

a design where an experiment is conducted in each of several groups that are alike in some important way (Example: groupings by gender, by age, by race, etc.)

Answer 69

blocking

Question 70

this happens when the levels of one variable are hopelessly mixed together with the levels of another variable (making it impossible to determine which levels are truly affecting the response variable of interest)

Answer 70

confounding