Bold black = question • Green = answer • Blue heading = original section break (e.g. Q2, Q3) from the source
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Population
The entire number of items in a large group. Basically the set of all the elements the study is about.
Sample
A subset of the population
Statistical Inference
The process of using data from a sample to gain information about the population
Descriptive Statistics
Uses numerical and graphical methods to explore data (e.g., look for patterns)
Compiled summary of the data analysis in numerical, tabular, or graphical form
Histogram
Summary count of items in each category in a single variable, in a tabular or graphical view
Average
Used as a measure to determine a central value or location from the data used
Index Number
Most widely utilized numerical descriptive statistic
Typically a compilation of several data sources and weighted to provide a consistent review of a measured
variable
Experimental Study
The researcher manipulates some of the variables and tries to determine how the manipulation influences other
variables
Observational Study
Researcher collects information not by influencing the variables in the study, but by simply observing the
variable in action (active or passive)
Data
Things about which information can be collected and analyzed (people, numerical information, geographical areas,
etc.)
Data Set
An rectangular array of information that contains the various categories of data collected for a specific study
Element
The individual and unique entry in a data set about which data has been collected, analyzed, and presented in the
same manner
Variable
A particular, measurable attribute that the researcher believes is needed to describe the element in their
study
Observation
All the information collected for each element in a study
, Cross-Sectional Data
Data collected at the same or approximately the same point in time
Time-Series Data
Data collected over several time periods
Statistics
Science of data
Collecting, classifying, summarizing, organizing, analyzing and interpreting information
Research data can be gathered in two ways:
1) Through existing information stored somewhere.
2) Direct collection of info by surveys, questionnaires, experimental testing.
Two types of statistical studies are?
A) Experimental
B) Observational
Two methods of data collection:
A) Simulations
B) Surveys
(Data Collection) Simulations:
Use mathematical or physical models to reproduce a situation or process.
Good way to study situations that are impractical or dangerous in real life. Cost effective & safe.
(Data Collection) Surveys:
Investigation of one or more characteristics of a population. Usually it’s people asking carefully crafted
interviews via phone, internet, or mail. Carefully worded questions to avoid bias.
Three elements of well-designed experiments:
1) Control.
2) Randomization.
3) Replication.
Confounding Variable:
Occurs when a researcher cannot discern which factors are influencing the variable.
Placebo Effect:
When a subject reacts favorably to a fake treatment.
Blinding:
Technique where the subjects don’t know whether they’re getting treatment or placebo.
Double-Blind Experiment:
Neither the experimenter nor the subjects know whether the subjects are receiving treatment or placebo.
Randomization:
Process of randomly assigning subjects to different treatment groups.
Blocks: