survey that includes every member of the
population

the technique of collecting information from a portion of the population

Representative sample: is a sample that represents the characteristics of the population as closely as possible.

Nonrandom sample :is a sample drawn in such a way that each element of the population has a chance of beingselected

Characteristics are called parameters

Population : Parameters are generally known

sample : Parameters are always known

Part of the group

is the value of a variable for an element

.............is a collection of observations on one or more variables.

is a variable that can be measured numerically.

discrete variable can assume only certain values with no intermediate values.

Discrete variable is a variable that can assume any numerical value over a certain interval

A ............ variable has no intrinsic ordering to its categories.

.................. data set :A data set consisting of observations on a single attribute

Bivariate data set : data set consisting of observations on three different attributes.

.............data set consisting of observations on two or more attributes

Bivariate data are a special case of multivariate data

each sample of the same size has the same chance (probability) of being selected.

we first divide the population into nonoverlapping subgroups, which are called strata

Cluster Sampling : the whole population is first divided into (geographical) subgroups called strata