Ap Stats - Ch.12 Vocab

Front 1

population

Back 1

entire group of individuals about whom we hope to learn

Front 2

sample

Back 2

a representative subset of a population, examined in hope of leaning about the population

Front 3

Bias

Back 3

any systematic failure of a sampling method to represent the population is bias. impossible to recover from bias. errors include: voluntary response, undercoverage of the population, nonresponse bias, response bias

Front 4

randomization

Back 4

best defense against bias, each individual is give a fair, random chance to be selected

Front 5

matching

Back 5

attempt to force a sample to represent a population -- may make better samples but no substitute for randomizing

Front 6

sample size

Back 6

number of individuals in a sample. the sample size determines how well the pop is sampled, not what fraction of the population is sampled

Front 7

census

Back 7

a sample that includes the entire population

Front 8

population parameter

Back 8

numerically valued attribute of a population. attempt to estimate from sampled data.

Front 9

statistic, sample statistic

Back 9

values calculated for sample data. correspond to and thus estimate a pop parameter

Front 10

representative

Back 10

sample is representative if the statistics computed from it accurately reflect the population parameters

Front 11

Simple Random Sample (SRS)

Back 11

a sample when every element is the sampling frame had an equal likelihood of being chosen

Front 12

sampling frame

Back 12

list of individuals from whom the sample is drwan

Front 13

sampling variability

Back 13

natural tendency of randomly drawn samples to differ

Front 14

stratified random sampling

Back 14

pop is divided into several sub pop or strata, and the samples are drawn from each stratum. each stratum is homogeneous within and heterogeneous without.

Front 15

cluster sample

Back 15

entire groups or clusters are chosen at random. each cluster is heterogeneous within and homogeneous without and each one is representative of the population

Front 16

multistage sampling

Back 16

use of multiple sampling techniques

Front 17

systematic sampling

Back 17

people are chosen systematically from the sample (every tenth person on the list) and as long as it begins at a random point and there is no variables in the order of the list that would affect the sample, the sample can still be representative

Front 18

voluntary response bias

Back 18

introduced when participants can choose whether to participate. generally attracts those who are the extremes...those who feel strongly

Front 19

convenience sample

Back 19

introduces bias b/c the representative population is not all convenient to sample

Front 20

undercoverage

Back 20

sample with less representation than the pop

Front 21

nonresponse bias

Back 21

bias introduced when a large percent of people choose not to respond

Front 22

response bias

Back 22

anything in survey design that influences response is response bias: question wording, dress of surveyor