Choosing a statistical
What are you trying to do?
Describe a sample or population
Measures of Central Tendency
Mean, Median, Mode
Measures of Dispersion
Range, standard deviation
Infer about a population from a
sample
What level of data ?
Interval
Ordinal
Nominal
Interval
Ordinal
Nominal
Chi Square
Goodness of fit
Interval
Ordinal
Nominal
Nonparametric tests
Mann Whitney U (2 samples)
Kruskal Wallace H Test (3 or more samples)
Interval
Ordinal
Relationship
or
Nominal
Difference ?
Relationship
or
Pearson r correlation
2 dependent variables
Difference?
Relationship
or
Difference
How many variables?
How many variables?
One Variable
Two Variables
One Variable
or
Two
Variables
2 way ANOVA
One Variable
How many groups?
or
Two Variables
How many groups?
One group
Two groups
More
than two Groups
One group
t test for single
 is known
 is unknown
Two groups
More than
two Groups
One group
Two groups
t test for 2 samples
independent samples
or
matched samples
More than
two Groups
One group
Two groups
More than
two Groups
One way ANOVA
3 or more levels
of the ind. Var.