Ch 8; Producing Data: Sampling

Question 1

Population

Answer 1

Entire group of individuals about which we want info.

Question 2

Sample

Answer 2

A part of the population from which we collect info.

Question 3

Sampling Design

Answer 3

Describes exactly how to choose a sample from the population.

Question 4

Sample Survey

Answer 4

Selects a sample from the population of all individuals we desire info. Base conclusions about population based on sample.

Question 5

Bad Samples (3)

Answer 5

Convenience Sample, Bias, Voluntary Response Sample

Question 6

Convenience Sample

Answer 6

A sample where individuals are selected by taking members of population easiest to reach.

Question 7

Bias

Answer 7

Design is biased if it systematically favours certain outcomes.

Question 8

Voluntary Response Sample

Answer 8

Consists of people who choose to participate by responding to a broad appeal. Biased b/c people w/ strong opinions most likely to respond.

Question 9

Simple Random Samples (SRS)

Answer 9

Consists of n individuals from the population chosen in a way that every set of n individuals has an equal chance to be the sample actually selected.

Question 10

Table of Random Digits

Answer 10

A long string of numbers 0,1,2,3,4,5,6,7,8,9 w/ 2 properties; 1) Each entry equally as likely to be any # & 2)Entries independent of each other.

Question 11

Inference

Answer 11

Process of drawing conclusions about a population on basis of sample data.

Question 12

What gives more accurate results?

Answer 12

Larger sample sizes.

Question 13

Stratified Random Sample

Answer 13

Classify population into groups of similar individuals (called strata). Then choose a separate SRS in each stratum & combine these SRSs to form the full sample.

Question 14

Cautions about Sample Surveys

Answer 14

Undercoverage, nonresponse, response bias, wording effect

Question 15

Undercoverage

Answer 15

Occurs when some groups in population left out of process of choosing sample

Question 16

Nonresponse

Answer 16

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

Question 17

Response Bias

Answer 17

Tendency of a person to answer questions on a survey untruthfully or misleadingly.

Question 18

Wording Effect

Answer 18

The possible effects on participants caused by the order of presented words or even the choice of the words themselves