Variables and Treatments
This variable is manipulated in an experiment to determine its effect on the response variable.
What is the explanatory variable?
This sampling method involves selecting individuals from the population in a way that every individual has an equal chance of being chosen.
What is simple random sampling?
This occurs when some members of a population are inadequately represented in a sample, leading to incomplete or skewed data.
What is undercoverage?
In this type of study, researchers do not manipulate variables but instead observe and measure outcomes in subjects as they naturally occur.
What is an observational study?
This principle involves using enough experimental units to distinguish treatment effects from random variation.
What is replication?
This variable measures the outcome or result of an experiment.
What is the response variable?
In this sampling technique, the population is divided into distinct groups based on a shared characteristic, and then a random sample is taken from each group.
What is stratified random sampling?
This type of bias arises when survey respondents self-select, meaning only individuals with strong opinions or specific characteristics may participate.
What is voluntary response bias?
This term refers to a study in which researchers intentionally impose a treatment or intervention on participants to observe its effect.
What is an experiment?
This is the process of randomly assigning experimental units to treatments to create roughly equivalent groups.
What is randomization?
These are the explanatory variables in an experiment, especially when multiple variables are being tested.
What are factors?
This method involves selecting groups at random from the population, and then surveying everyone in the selected groups.
What is cluster sampling?
This type of bias occurs when participants give answers they think are socially acceptable or desirable rather than truthful.
What is response bias?
This is the term for the group in an experiment that does not receive the treatment or intervention, but is used for comparison to the treatment group.
What is the control group?
This principle involves keeping all other variables besides the treatment constant to isolate its effects.
What is control?
These are the specific values or categories that a factor can take in an experiment.
What are levels?
This sampling method involves selecting every nth individual from a list or population, where 'n' is a fixed interval, such as every 10th person.
What is systematic sampling?
This bias occurs when individuals chosen for a survey are not reachable, fail to respond, or refuse to participate, leading to a lack of representation of the entire population.
What is nonresponse bias?
This type of study is often used when it is unethical or impractical to manipulate variables, such as in studying the effects of smoking on health.
What is an observational study?
This design pairs similar experimental units and assigns one to each treatment to reduce variability.
What is a matched-pairs design?
This term describes the specific combinations of factor levels applied to experimental units in an experiment.
What are treatments?
This is the term for a sampling method where participants are chosen based on their willingness to participate, often leading to bias because only those with strong opinions may respond.
What is voluntary response sampling?
This type of bias can happen if a survey question is worded in a way that influences the respondent's answer.
What is wording bias?
This key feature of an experiment allows researchers to reduce the effect of confounding variables by randomly assigning subjects to different treatment groups.
What is random assignment?
This experimental principle reduces the impact of confounding variables by grouping similar experimental units and randomizing within each group.
What is blocking?