Instruction Cards Flashcards
Answering Questions
State three principles which help ensure significance of an experimental study
- Clear hypothesis that addresses a specific question
- Large sample size (over 30)
- Use control variables to isolate effect of independent variables
How does direct control of confounding variables increase the quality of an experiment?
improves the quality of an experiment by reducing unwanted influence on the results, ensuring that any observed effects are due to the independent variable, increasing the validity
How does randomization affect the quality of an experiment?
improves the quality of an experiment by helping to distribute confounding variables evenly across treatment groups
Why is blinding potentially important for experimental design (particularly when involving humans)?
Blinding is important in experimental design because it helps prevent bias in the results by ensuring that participants (and sometimes researchers) do not know which group they are in
Differentiate between the goals of experimental and observational studies.
The goal of an experimental study is to determine cause-effect relationships by manipulating one or more variables while controlling others.
The goal of an observational study is to explore relationships and patterns by observing variables without intervention.
How are blocking and stratifying analogous? How are they different?
Blocking involves grouping units with similar characteristics to reduce variability within those groups and isolate the effect of the treatment.
Stratifying involves dividing the entire population into subgroups (strata) based on a specific characteristic, ensuring equal representation of these subgroups in each treatment group, which helps to ensure more precise estimates.
Differentiate between stratified random sampling and cluster random sampling.
Stratified random sampling involves dividing the population into distinct subgroups based on specific characteristics, and then randomly sampling from each stratum to ensure representation from each group.
Cluster random sampling involves dividing the population into clusters (usually based on naturally occurring groups, like schools or neighborhoods), and then randomly selecting entire clusters to be included in the sample.
Why can’t observational studies establish causal relationships?
Observational studies cannot establish causal relationships because they do not involve the manipulation of variables
What does it mean for a statistic to be an unbiased estimator?
A statistic is an unbiased estimator if the expected value of that statistic is equal to the true population parameter it is estimating
