Design of a statistical study
Experimental design
Sampling techniques
Data
Levels of measurement
100
observational study
A researcher does not influence the responses
100
Confounding variable
when an experimenter cannot tell the difference between the effects of different
100
Census
a count or measure of an entire population
100
Status
the Latin word meaning “state”
100
Nominal level
qualitative only, using only names, labels, or qualities
200
Experiment
a researcher deliberately applies a treatment before observing the responses
200
Blinding
a technique where the subjects do not know whether they are receiving a treatment or placebo
200
Sampling error
the difference between the results of the sample and those of the population
200
Data
information coming from observations, counts, measurements, or responses
200
Ordinal level
qualitative and quantitative, arranged in order, or ranked, but differences between data entries are not meaningful
300
Treatment group
treatment is applied to part of the population
300
Randomization
a process of randomly assigning subjects to different treatment groups
300
Random sample
every member of the population has an equal chance of being selected
300
Statistics
the science of collecting, organizing, analyzing, and interpreting data in order to make decisions
300
Interval level
can be ordered, and meaningful differences between data entries can be calculated
400
Control group
the part of the population on which no treatment is applied
400
Blocks
groups of subjects with similar characteristics
400
Simple random sample
a sample in which every possible sample of the same size has the same chance of being selected
400
Population
the collection of all outcomes, responses, measurements, or counts that are of interest
400
Ratio level
similar to data at the interval level, with the added property that a zero is an inherent zero
500
Experimental units
the subjects in the treatment and control groups
500
Sample size
the number of subjects in a study
500
Sample
a count or measure of part of a population
500
Inappropriate sampling
the data cannot be used to draw conclusions about the population
500
Inherent zero
implies none
M
e
n
u