Define the Population Parameters
Sample statistics estimate population parameters based on data, and the choice of variables and measurement scales influences the type, size, and properties of the sample used for analysis.

Define the Selection and Recruiting Protocols
Researchers must carefully select participants and ensure their cooperation through proper methods and incentives.

Ethical Issues and Their Solutions
Ethical sampling issues involve deception, incentives, and quality, requiring careful management of consent, confidentiality, and sample selection standards.

Convenience Sampling
the least reliable
design but normally
the cheapest and easiest
sample to draw

Snowball Sampling
sampling locates hard-to-find respondents through referrals, making it ideal for qualitative studies
and niche populations.

Simple Random Sampling
the purest form of probability sampling, where each population element has an equal and known chance of selection.

Systematic Sampling
simplicity and flexibility

Proportionate vs Disproportionate Sampling
Proportionate stratified sampling divides a population into strata proportional to their size,
while disproportionate is used when
strata variances or costs vary.

Area Sampling
applied to
national pop.,
county pop.,
and where there are
well-defined political or
natural boundaries

Double Sampling
more convenient or economical to collect some information by sample and then use this information as the basis for selecting a subsample for further study

Sample versus Census
Sampling allows us to draw conclusions about an entire population by examining a subset of it.

Lower Cost
The economic advantages of taking a sample rather than a census are massive.

Greater Speed of Data Collection
using a sample drawn from a target population will
always take less time than conducting a census.

Availability of Population Cases
Drawing a sample is also the only process
possible if the population is infinite.

Better Quality Results
“the possibility of better interviewing (testing), more thorough investigation of missing, wrong, or suspicious information, better supervision, and better processing than is
possible with complete coverage

Accuracy
Accuracy is the degree to
which bias is absent from the sample

Precision
measured by the standard error of estimate, a type of standard deviation measurement;

Sample Size
If a census is chosen, then the researcher
need not determine sample method or size

A Community as Sample Frame
a collection of digitally literate individuals
who want to engage with each other
and with a company to share ideas, concerns,
information and to assist with decision making

Complex random

• Systematic
• Cluster
• Stratified
• Double

Purposive

• Judgment
• Quota  
• Snowball

Judgment
selects sample members to conform to some criterion.

Quota
to improve
representativeness