Study Design Flashcards
Descriptive Studies
studies which describe things e.g., surveys, questionnaires finding out general stuff
Analytic Studies
studies which test hypotheses: Experimental studies e.g., randomised controlled trials OR Observational studies e.g., cohort studies; case-control studies
Population
a complete set of entities or elements or units or people that we wish to describe or make inference about
Sample
a subset of a population
Sampling Frame
a list of items in a population from which a sample is drawn. Rarely coincides with the entire population of interest
Sources of Error
Random error (chance) OR Systematic error in a descriptive study (bias)
Random error (chance)
Error due to variability of things we’re measuring
Systematic error (bias)
Error due to bias (how close we are to the subject)
Increasing sample size can reduce…
Random error but NOT systematic error
Probability sampling
helps to justify the statistical models which will be introduced in this course
Simple random sample
For a finite population of size N draw a sample of size n such that each possible sample has the same probability of being selected.
Stratified sampling