Data Collection Principles

Flashcards covering key vocabulary and concepts from a lecture on data collection methods, sampling techniques, study designs, and experimental design.

Population

The entire group of individuals or objects that you want to study.

Sample

A smaller, more manageable group selected from the population to represent the larger group.

Parameter

A numerical value describing an entire population's characteristics.

Statistic

A numerical value that describes a characteristic of a sample.

Individuals

The objects described by a set of data (can be people, animals, or things).

Variables

Characteristics or measurements that we are interested in studying. Can be quantitative (numerical) or categorical (qualitative).

Quantitative Variables

Numerical measurements, such as age, height, weight, or income.

Categorical Variables

Categories or labels, such as gender, race, occupation, or favorite color.

Data

Actual values of the variables (raw information) that we collect and analyze.

Simple Random Sampling

A sampling method where every combination of n individuals is equally likely to be selected.

Stratified Sampling

Involves dividing the population into distinct subgroups (strata) based on specific characteristics and taking a random sample from each stratum.

Cluster Sampling

Involves dividing the population into naturally occurring groups (clusters), randomly selecting a few clusters, and including all individuals within those clusters in the sample.

Systematic Sampling

Involves selecting every 'nth' individual from a list of the population, starting from a randomly chosen point.

Explanatory Variable

The variable that may cause or influence a change in another variable (also known as the independent variable).

Response Variable

The variable that is affected by the explanatory variable (also known as the dependent variable).

Observational Study

Researchers observe and record data on variables as they naturally occur, without any intervention or manipulation.

Sample Survey

A specific type of observational study where individuals self-report the values of variables, often by providing their opinions or answering questions.

Experiment

Researchers intentionally manipulate one or more variables (the explanatory variables) to observe their effect on another variable (the response variable).

Treatments

The different values of the explanatory variable in an experiment.

Experimental Unit

A single object or individual being measured in an experiment.

Randomization

Randomly assigning participants to different groups to minimize bias.

Replication

Repeating the experiment with a large sample size or reproducing the entire study to confirm previous findings.

Control Group

A group of participants in an experiment who do not receive the experimental treatment, serving as a baseline for comparison.

Placebo

An inactive treatment that has no real effect on the response variable, used in control groups.

Placebo Effect

When patients improve solely because they believe they are receiving treatment, regardless of whether they are actually receiving the treatment.

Blinding

A technique used to prevent participants and/or researchers from knowing who is receiving the experimental treatment and who is receiving the placebo.

Single-Blind

Only the participants are unaware of their treatment group assignment.

Double-Blind

Both the participants and the researchers interacting with them are unaware of the treatment group assignments.

Randomized, Controlled, Double-Blind Experiment

The most reliable way to determine whether the explanatory variable is actually causing changes in the response variable.