###
Discrete Variables

Variables that can take on a finite set of values (ending)

###
Continuous Variables

Variables that can take on an infinite set of values (non-ending)

###
Real Limits

An extra tenth, midway between the given value and the next lower/higher value (9.87 = 9.865/9.875)

###
Population

An entire set of possible observations that may be made

###
Sample

A collection of numbers drawn from a population

###
Independent Variable

The variable that is varied or manipulated by the researcher

###
Dependent Variable

The response that is measured

###
Experimental Study

Describes behavior with identifying the cause

###
Non-experimental Study

Describes behavior but does not identify causes

###
Quasi-experiment

An observational study with subjects that are already grouped from existing categories

###
Nominal Scale

Mutually exclusive categories (category)

###
Ordinal Scale

Mutually exclusive categories and logical natural order (ranks)

###
Interval/Ratio Scale

Mutually exclusive categories, logical and natural order with equal differences between values

###
Histogram

Touching bar graph with interval/ration data

###
Bar Chart

Non-touching bar graph with nominal/ordinal data

###
Frequency Polygon

Line graph with interval/ratio data

###
Unimodal Distribution

One peak in the graph

###
Bimodal Distribution

Two peaks in the graph

###
Symmetrical Tails

Equidistant lengths from the mean

###
Skewed Tails

Differing lengths from the mean

###
Kurtosis

How pointed or flat the curve is

###
Advantages of Mode

Unaffected by extreme scores, is an actual score in the distribution, can use mode with all data

###
Disadvantages of Mode

May not represent data well, can easily be affected by one or two scores

###
Advantages of Median

Unaffected by extreme scores, can use with ordinal or interval/ratio data (can represent skewed data)

###
Disadvantages of Median

May not represent data well, value you may not exist as a real score, cannot use with nominal data

###
Advantages of Mean

Every point contributes to the mean, can be used in equations, unbiased estimate of population

###
Disadvantages of Mean

Influenced by extreme scores, can be used with interval/ratio, value may not exist in the data

###
Mode = Mean = Median

Any normal distribution

###
Use Mode with...

Nominal, Ordinal, Interval/Ratio data

###
Use Median with...

Ordinal, Interval/Ration data

###
Use Mean with...

Interval/Ratio data

###
Variability

Indicates the spread of distribution and the degree to which scores are clustered about the mean

###
Measures of Variability

Range, Standard Deviation, Variance

###
Degrees of Freedom

The number of values in a data set that can vary

###
Inflection Points

A point where a line changes from concave to convex

###
Percentiles

Values that divide the distribution into 100 equal parts

###
Percentile Rank

A particular person's rank relative to the reference group

### Please allow access to your computer’s microphone to use Voice Recording.

## We can’t access your microphone!

### Click the icon above to update your browser permissions above and try again

Example:

### Reload the page to try again!

Reload

## Press Cmd-0 to reset your zoom

## Press Ctrl-0 to reset your zoom

### It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

## Your microphone is muted

### For help fixing this issue, see this FAQ.