Chap. 11

Question 1

Population

Answer 1

an entire group of individuals you want information on

Question 2

Sample

Answer 2

smaller group of individuals within the population

Question 3

What is the major rule for a sample?

Answer 3

has to be representative

Question 4

Sample surveys

Answer 4

designed to ask questions of a small group of people in the hope of learning something about the entire population

Question 5

W’s of sampling

Answer 5

who: sample drawn
when and how: drawing the sample depends on what is practical
why: the population we are interested in

Question 6

Biased sampling

Answer 6

under or overestimating some characteristics of the population

Question 7

Common errors of biased sampling

Answer 7

relying on voluntary responses
under coverage of the population
nonresponse bias
response bias

Question 8

Randomization

Answer 8

best defense against bias - each individual is given a fair, random chance of selection

Question 9

Sample size

Answer 9

number of individuals in a sample

Question 10

What does sample size determine?

Answer 10

how well the sample represents the population

Question 11

Does the fraction of the population determine how well the population is represented?

Answer 11

no

Question 12

Census

Answer 12

a sample that consists of the entire population

Question 13

Population parameter

Answer 13

the numerical valued attribute of a model for a population

Question 14

How to know the true value of a population parameter (mean income of all employed people in the country)

Answer 14

hope to estimate it through sampled data

Question 15

Statistic / sample statistic

Answer 15

values calculated for sampled data

Question 16

Which statistics are most favorable?

Answer 16

those that correspond to and thus estimate a population parameter

Question 17

Representative

Answer 17

sample said to be representative if the statistics computed it accurately reflect the corresponding population parameters

Question 18

Simple random sample (SRS)

Answer 18

sample in which each set of n elements in the population has an equal chance of selection

Question 19

Sampling frame

Answer 19

list of individuals from whom the sample is drawn is called the sampling frame

Question 20

What does it mean to be outside of the sampling frame?

Answer 20

individuals who may be inside the population of interest but aren’t in the sampling frame

Question 21

Sampling variability

Answer 21

natural tendency of randomly drawn samples to differ from one another

Question 22

Stratified random sample

Answer 22

population is divided into several subpopulations or strata. random individuals are drawn from each group so that the sample includes individuals from each, in a representative proportion. reduces variability

Question 23

Cluster sample

Answer 23

entire groups or clusters are chosen at once. usually convenient, practical, or less costly.

Question 24

Multistage sample

Answer 24

sampling schemes that combine several sampling methods

Question 25

Systematic sample

Answer 25

drawn by selecting individuals systematically from a sampling frame. representative when there is no relationship between the order of the sampling frame (every 10th person)

Question 26

Pilot survey

Answer 26

small trial run to a survey to check whether questions are clear. reduces errors to questions that are up to interpretation or ambiguous

Question 27

Voluntary response bias

Answer 27

bias introduced to a sample when individuals can choose on their own weather to participate in the sample. invalid and cannot be recovered

Question 28

Convenience sample

Answer 28

consists of individuals who are conveniently available. every individual in the population is not equally represented

Question 29

Undercoverage

Answer 29

biases the sample in a way that gives part of the population less representation

Question 30

Nonresponse bias

Answer 30

bias introduced when a large fraction of those who are sampled fail to respond.

Question 31

What type of response is considered nonresponse?

Answer 31

voluntary response bias

Question 32

Response bias

Answer 32

Anything in a survey design that influences responses falls under the heading of response bias. the wording of a question creates response bias, or who’s asking the question