Statistics & Probability
Collecting Data flashcards
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- What does “Simple Random Samples” mean?Sampling Methods
- A design with equal selection probability for every subset of the specified size.
- What important condition applies to simple random samples?Sampling Methods
- Equal individual inclusion probabilities alone do not establish a simple random sample.
- What does “Systematic Sampling” mean?Sampling Methods
- A sample selected at regular list intervals after a random start.
- What important condition applies to systematic sampling?Sampling Methods
- Periodicity in list order can bias a systematic sample.
- What does “Stratified Sampling” mean?Sampling Methods
- A design that samples separately within defined population subgroups.
- What important condition applies to stratified sampling?Sampling Methods
- Sampling within every stratum is different from selecting only some clusters.
- What does “Nonresponse Bias” mean?Bias
- Distortion arising when responding units differ from missing invited units.
- What important condition applies to nonresponse bias?Bias
- A high response rate does not guarantee absence of nonresponse bias.
- What does “Undercoverage” mean?Bias
- Exclusion of target-population units from the sampling frame.
- What important condition applies to undercoverage?Bias
- Larger samples cannot by themselves repair an incomplete sampling frame.
- What does “Observational Comparisons” mean?Observational Studies Versus Experiments
- A comparison of measured groups without randomized exposure allocation.
- What important condition applies to observational comparisons?Observational Studies Versus Experiments
- Association alone does not establish causation.
- What does “Random Assignment” mean?Observational Studies Versus Experiments
- Chance-based allocation of experimental units to treatment conditions.
- What important condition applies to random assignment?Observational Studies Versus Experiments
- Random assignment and random sampling serve different purposes.