A probability sample is a sample in which each member of the population has a known, nonzero chance of being selected for the sample. There are five main types:
Definition6.1.1.
simple random sample: a sample in which every member of the population has an equal chance of being chosen
systematic sampling: every \(k\)th member of the population is chosen for the sample; \(k=\frac{\text{size of population, }N}{\text{size of sample, }n}\)
stratified sampling: the population is divided into mutually exclusive groups (strata) and randomly chosen members from the groups are chosen for the sample
cluster sampling: the population is divided into mutually exclusive groups (clusters) and then one or more clusters is chosen for the sample
convencience sample: members of a sample are chosen because they are easily accessible
Definition6.1.2.
resampling: the statistical technique in which many samples are repeatedly drawn from a population
Exercise6.1.3.
(Donnelly, Your Turn 1)
Identify the type of sampling technique used below.
The first Monday of each month, customers who come to a store are asked to fill out a satisfaction survey.
systematic
simple random
stratified
cluster
convenience
Exercise6.1.4.
(Donnelly, Your Turn 1)
Identify the type of sampling technique used below.
I randomly select four stores in a mall and ask each customer in those stores about his or her opinion of the latest health care legislation.
systematic
simple random
stratified
cluster
convenience
Exercise6.1.5.
(Donnelly, Your Turn 1)
Identify the type of sampling technique used below.
I position myself on a busy intersection of a city street and ask people what their opinions are of a local sports team.
systematic
simple random
stratified
cluster
convenience
Exercise6.1.6.
(Donnelly, Your Turn 1)
Identify the type of sampling technique used below.
Sixty percent of students attending a certain college are women. A random sample of college students is constructed that consists of 60% women from the student population to ask what their opinions are of the college’s food service.
systematic
simple random
stratified
cluster
convenience
Exercise6.1.7.
(Donnelly, Your Turn 1)
Identify the type of sampling technique used below.
Using computer software, a manager randomly selects 20 employees to participate in a job satisfaction survey.
