Statistics – The practice of collecting, analyzing, interpreting, and reporting
1. Descriptive Statistics: Organize, summarize, and communicate numerical
2. Inferential Statistics: Use data from sample and generalize about
Populations and Samples
Population – The set of all observations of interest in a particular study.
Sample- A set of observations drawn from a population of interest for inclusion in a
Variables – Observation of physical, attitudinal, and behavioral characteristics that
can take on different values.
Discrete Observation- Can take on only specific values, ex. Whole #’s.
Continuous Variables - Can take on a full range of values (e.g. #’s to several
decimals) an infinite # of potential values exists.
1. Nominal Variables – Used for observations that have categories, or names
as their values.
2. Ordinal Variables – Observations that have rankings as their values (1 ,
2 , 3 …)
1. Interval Variables – Used for observations that have #’s as their values;
the distance (or interval) between pairs of consecutive #’s is assumed to
2. Ratio Variables – Variables that meet the requirements of an interval
variable but also have a meaningful zero point.
- Sometimes interval and ratio variables are referred to as scale variables.
Scale Variables – A variable that meets the criteria for an interval or ratio variable. Independent, Dependent, & Confounding Variables
- 3 types of variables considered in research: