Qualitative vs. Quantitative
Eye Color
Quantitative
Each member of the population is equally likely to make up the sample.
Simple Random Sample
Investigator assigns treatments to the participants at random.
Randomized Experiment
Consist of Prospective, Retrospective, and Cross-Sectional studies.
Cohort Studies
Responses are skewed due to a strong opinion and a voluntary participation.
Voluntary Response Bias
Classify individuals into categories
Qualitative
A sample that is not drawn by a well-defined random method.
Sample of Convenience
Assignment to treatment groups is not made by the investigator
Observational Study
The general category branching into both cohort and case-control studies.
Observational Study
Outcome of leaving questions blank in a survey.
Non-response Bias
How much or how many of a condition there is.
Quantitative
The population is divided into groups, then a simple random sample is drawn from each group.
Investigator wants to determine whether a certain drug will decrease depressive moods. They choose half of the sample to get the drug at random, and half to take a placebo. Mood is measured after 1 month.
Randomized Experiment
A study where measurements are taken at one point in time.
Cross-Sectional Cohort Study
When questions are worded in a way that encourages a particular response.
Leading Question Bias
Behavior
Qualitative
Items are drawn from the population in groups
Cluster Sampling
Differences in outcomes are due to chance or, in bigger differences, treatments.
Randomized Experiment
A group of subjects are studied OVER TIME to determine whether various factors of interest are associated with an outcome
Prospective Cohort Study
Often leads to the selection of analyses that correspond with the hypothesis... Happens when a researchers opinions are skewed.
Self-interest Bias
MRI data
Quantitative
Items are ordered. Every Kth item is chosen to be included in the sample
Systematic Sampling
An investigator wants to determine whether exercise decreases depressive symptoms. They send out a survey to the NIH asking participants to report their level of activity and level of depressive symptoms. Correlations are assessed.
Observational Study
A study in which two samples are drawn, one of which consisting of the people with the disease/case of interest, and the other of which consisting of the controls (no disease).
Case-Control Study
Some members of the population are more likely to be included in the sample than others.