placebo
a sham treatment designed to have no known therapeutic value.
data
facts and statistics collected together for reference or analysis.
statistics
a fact or piece of data from a study of a large quantity of numerical data.
sample
a smaller, manageable version of a larger group
population
A population is a whole, it's every member of a group
categorical
Categorical variables represent types of data which may be divided into groups
what category does race, sex, age group, and educational level?
categorical data
quanititve data
he value of data in the form of counts or numbers where each data set has a unique numerical value
Levels of Mesurement
nominal, ordinal, interval, and ratio data
nominal level of measurement
the least precise and informative
ordinal level of measurement
the second of the four measurement scales
interval level of measurement
like the ordinal scale, places variables in order
ratio level of measurement
the highest of four hierarchical levels of measurement
simple random
a subset of a statistical population in which each member of the subset has an equal probability of being chosen.
systematic
probability sampling method where researchers select members of the population at a regular interval
convenience sampling
a method adopted by researchers where they collect market research data from a conveniently available pool of respondents.
cluster
Researchers divide a population into smaller groups known as clusters. They then randomly select among these clusters to form a sample.
stratified
a method of sampling that involves dividing a population into smaller groups-called strata.
continuous data
data that can take any value
discrete
a count that involves integers — only a limited number of values is possible
observational study
A type of study in which individuals are observed or certain outcomes are measured.
experiment
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parameter
A method of assigning participants to groups in which pairs of participants are first matched on some characteristic and then individually assigned randomly to groups.
single-blind study
researcher doing the study knows which treatment or intervention the participant is receiving until the trial is over.
double-blind study
A type of clinical trial in which neither the participants nor the researcher knows which treatment or intervention participants are receiving until the clinical trial is over.
retrospective study
A study that compares two groups of people: those with the disease or condition under study (cases) and a very similar group of people who do not have the disease or condition (controls).
cross sectional study
a type of observational research that analyzes data of variables collected at one given point in time across a sample population or a pre-defined subset.