Class 12 key terms

Accesible population

The group of people from which the sample can actually be drawn.

Biological/ physiologicalmeasurement

Measurement of biological or physical traits, like blood pressure or heart rate

objective data

Ethical considerations: invasiveness and participant comfort

Closed ended item

A survey question with fixed answer choices.

Cluster sampling (multistage sampling)

Sampling where groups (clusters) are randomly selected, not individuals.

Economical for large.dispersed populations

Higher sampling error, more complex analysis '

Useful when theres noncomplete populaiton list

Concealment

Hiding study details from participants or researchers to reduce bias.

Consistency

The degree to which results are repeatable over time

Convience sampling

Easiest and most common method

Choosing participants who are easy to reach.

Ex: putting up flyers 

High risk of bias and weak generalizability

Data saturation

The point when no new information is gained from additional data

Debriefing

Explaining the study to participants after it ends.

Delimitations

Boundaries set by the researcher for the study (e.g., age range, location).

Effect size

A measure of how strong a relationship or difference is in the study.

Element

A single member of the population (e.g., one patient).

Eligibility criteria

Rules that determine who can or cannot participate.

External criticism

Evaluating the trustworthiness of a study’s sources or data.

Heterogenity

Diversity or variety within a sample or population.

Homogenity

When participants are very similar in characteristics.

Internal criticism

Evaluating the accuracy and logic of a study’s findings.

Intervention

The treatment or action being tested in a study.

Internal fidelity

How closely the intervention is delivered as planned.

Interview

A data collection method where questions are asked verbally.

Likert-type scale

A scale where participants rate agreement, e.g., 1–5.

Matching

Pairing participants with similar characteristics across groups.

Measurement 

The process of assigning numbers or labels to variables.

Multistage sampling

Sampling done in multiple steps, often combining methods.

Network sampling

Using social networks to identify participants.

Non probability sampling

Sampling where not everyone has an equal chance of selection.

Objective

Free from personal bias; based on facts.

Open ended item

A survey question that allows participants to respond in their own words.

Ooperational definition

How a variable is defined for measurement in a study

Operationalization

Turning abstract concepts into measurable variables.

Pilot study

A small test study done before the main study

Population

The entire group a researcher wants to study

Probability sampling

Sampling where everyone has a known, nonzero chance of being selected.

Purposive sampling

Selecting participants who meet specific criteria for the study.

Quota sampling

Sampling until a set number of participants from subgroups is reached (quota is filled)

Ensures some representativeness

Non probability, son can have bias and limited generalizability

Useful when populaiton characteristics are known

Questionnaire

A written set of questions used to collect data.

Random selection

Choosing participants so everyone has an equal chance of being picked.

Reactivity

When participants change their behavior because they know they are being observed.

Records or available data

Using existing information like charts or databases.

Representative sample

A sample that reflects the characteristics of the population

Sample

A subset of the population selected for study.

Sampling frame

A list of all members of the population from which the sample is drawn

Sampling unit

The individual element chosen from the population.

Sampling interval

The gap between selected participants in systematic sampling

Scale

A tool for measuring variables (e.g., rating scales).

Scientific observation

Collecting data in a systematic, objective way.

Simple random sampling

Every individual has an equal chance of being selected

Maximizes representativeness, minimizes bias

Time consuming, may need complete population list

Snowball effect sampling

Participants refer others to join the study.

Social desireability

When participants answer in ways they think are acceptable or favorable.

Stratified random sampling

Dividing the population into homegenous subgroups (Strata), then randomly sampling within each.

Random selection, enahances representativeness and reduces bias

Need to have detailed info about population

Systemtic sampling

Selecting every nth element from a population list

Efficient and easy to implement

Can be biased if the lost has patterbs

Needs random starting point to mainatin randomness

Target population

The entire group the researcher wants to generalize findings to.

Theoretical sampling

Selecting participants based on their ability to provide rich data for theory development.

Probability sampling methods

• Simple Random Sampling

• Systematic Sampling

• Stratified Random Sampling

• Cluster Sampling

• Multistage Sampling

Non probability sampling methods

• Convenience Sampling

• Purposive (Judgmental) Sampling

• Quota Sampling

• Snowball (Network) Sampling

• Theoretical Sampling

If not specified, what sampling method can we assume quantitative studies use?

Convenience

If not specified, what sampling method can we assume qualtitative studies use?

Purposive

What does non probabaility (qualitative) sampling aim for

Depth and meaning (not generalizability)

Power analysis

Statistical methods used to deetermine sample size

If a small effect size is anticipated what is needed?

A lerger sample (opposite is also true)

Kappa statistics

Measures interlayer agreement, showing hownconsitently different data collectors record similar results

Observation methds of data collectio

Systeamtic wathcing and recording of behavuours, events and conditions

Can be structurede or unstructured

Usefyl for stuyding nonverbal behavuours, interactions and contexts