Statistics Ch. 1

Statistics

Collecting, presenting, analyzing, and interpreting data

Population

the entire group of individuals about which we want information

Sample

a subset of the population

Sampling frame

a list of population members from which a sample is drawn

Statistic

a number that describes a sample

Parameter

a number that describes a population

Samples should be...

Representative, Reliable, No bias (Good frame, prob. based methods, sufficient size)

Voluntary Response

Individuals can choose on their own whether to participate in the sample. (Online polls)

Convenience

Individuals easiest to survey. (Sidewalk polls)

Stratified Sample

Population divided into strata (subgroups), the SRS used on the groups. Used to obtain sample that equally represents several dissimilar groups.

Cluster Sample

A population is divided into groups, called clusters. All of the members in one or more of the clusters are selected.

Biased samples

samples that are not representative of the larger group