Problem Solving
An inquiry that may have multiple answers or is based on data that varies.
Statistical Question
The entire group of individuals we want information about.
Population
Data Collection method that does not attempt to influence the responses or impose a treatment.
Observational Study
When subjects in an experiment will respond favorably to any treatment, even an inactive treatment.
Placebo Effect
A sample that consists of individuals from a population that are easy to reach.
Convenience Sample
Inference on a population may be made when a sample is selected this way.
Random Selection
Census
When a treatment is imposed on individuals to measure their response.
Experiment
When neither the subjects nor those who interact with them and measure the response variable know which treatment the subject received.
Double-blind Experiment
A sample that consists of people who choose to be in a sample by responding to an invitation.
Voluntary Response Sample
Inference can be made about cause and effect if this is used to select individuals for the groups.
Random Assignment
A subset of individuals in a population from which we collect data.
Sample
When two variables are associated in such a way that their effects on a response variable cannot be distinguished from each other.
Confounding
When either the subject or the people who interact with them and measles the response variable don't know which treatment a subject is receiving.
Single-blind Experiment
When some members of a population are less likely or unable to be chosen for the sample.
Under coverage
Data collection methods are approved by an institutional review board, there is informed consent, and confidentiality.
Data Ethics
A method of selecting individuals from a population using a chance process. Inference about the population may be made.
Random Sample
We cannot infer this relationship with an observational study because there may be potential confounding.
Cause and Effect
When treatments are assigned to experimental units using a chance process. This prevents confounding and inference about cause and effect can be made.
Random Assignment
When individuals chosen for a sample can't be contacted or refuse to participate in.
Nonresponse
This process involves four steps: Ask questions, collect data, analyze data, and interpret the results.
Statistical Problem-Solving Process
When random samples of the same size from a population produce different results. This can be reduced by increasing the size of our samples.
Sampling Variability
When an observed difference in responses between groups is so large that it is unlikely to be explained by chance variation. (5% cutoff)
Statistically Significant
A group in an experiment to provide a baseline for comparing the effects of other treatments. This group may be given a placebo, an active treatment, or no treatment at all.
Control Group
This occurs when there is a consistent pattern of inaccurate responses to a survey question that may be caused by the wording of a question, characteristics of the interviewer, lack of anonymity, etc.
Response Bias