View source for Types of statistical tests

==Background==
*There are many statistical tests used for biomedical research.  The type of test to be used depends on the type of data, population type, distribution, and number of groups. 
*This article lists statistical tests by data type and sample requirements.

==Descriptive Statistics==
{|class="wikitable"
!colspan="3"|Descriptive Statistics with one variable/outcome
|-
| align="center" style="background:#f0f0f0;"|'''Scale/Type of Measurement'''
| align="center" style="background:#f0f0f0;"|'''Measure'''
| align="center" style="background:#f0f0f0;"|'''Statistic'''
|-
|''Ratio or Interval'' / (continuous/numerical)<br>'''Normally Distributed'''||Proportion of normal distribution below Z score||Z
|-
| ''Ratio or Interval'' / (continuous/numerical)<br>'''Normally Distributed'''||Z score at upper end of proportion of standard normal curve||Z
|-
|rowspan="2"|Ratio or Interval (continuous/numerical)<br>'''Normally Distributed'''||Central Tendency||Mean
|-
||Dispersion||SD
|-
|rowspan="2"|''Ratio or Interval''/(continuous/numerical)<br>'''Not Normally Distributed'''||Central Tendency||Median, mode
|-
| |Dispersion||Range, Interquartile Range (IQR)
|-
|rowspan="2"|''Ordinal (ranks)''||Central Tendency||Median, mode
|-
||Dispersion||Range, IQR
|-
|rowspan="2"|''Nominal (categories)''||Central Tendency||Mode
|-
||Dispersion||#of categories
|}

==One Sample==
{|class="wikitable"
!colspan="3"|Comparison of One Sample to a Population
|-
| align="center" style="background:#f0f0f0;"|'''Scale/Type of Measurement'''
| align="center" style="background:#f0f0f0;"|'''Requirement'''
| align="center" style="background:#f0f0f0;"|'''Test'''
|-
| Ratio or Interval<br>(continuous/numerical)||'''Normal distribution or n>30'''||One sample t
|-
|rowspan="3"|Nominal (categories)||||One sample binomial
|-
| |||Confidence interval for proportion
|-
| |'''np and n(1-p) >5'''||Z approximation
|}

==Two or more Groups==

{|class="wikitable"
!colspan="5"|Comparison of Two or More Independent Samples (Groups) (one independent/predictor variable)
|-
| align="center" style="background:#f0f0f0;"|'''Scale/Type of'''
| align="center" style="background:#f0f0f0;"|'''#of Samples (Groups)'''
| align="center" style="background:#f0f0f0;"|'''Requirement'''
| align="center" style="background:#f0f0f0;"|'''Test'''
|-
|rowspan="5"|Ratio or Interval(continuous/numerical)||rowspan="3"|2 || '''Normal distribution''' <br>or n>30<br>and '''Equal variances''' || T test
|-
| |'''normal distribution''' <br>or n>30||Welch's T test
|-
| | ||Rank Sum Test
|-
|rowspan="2"|>2||Normal distribution <br>or n>30 <br> Homogeneous variance||Analysis of Variance (ANOVA)
|-
| | ||Kruskal-Wallis Test<ref>Kruskal-Wallis Test. Statisticslecturescom. 2017. Available at: http://www.statisticslectures.com/topics/kruskalwallis/. Accessed May 22, 2017.</ref>
|-
|rowspan="2"|Ordinal (ranks) or Discrete Numerical ||2|| ||Rank Sum Test
|-
|>2 || ||Kruskal-Wallis Test
|-
|rowspan="5"|Nominal (categories) || 2 || || Fisher's Exact test<br>Chi Squared 
|-
|rowspan="3"|2 ||rowspan="3"|Expected values >5 || Chi Squared
|-
| | Relative Risk (Rate Ratio)
|-
| | Odds Ratio
|-
|≥2 || Expected values >5 ||Chi Squared
|}


{|class="wikitable"
!colspan="5"|Comparison of Two or More Independent Samples (Groups) (one independent/predictor variable)
|-
| align="center" style="background:#f0f0f0;"|'''Scale/Type of'''
| align="center" style="background:#f0f0f0;"|'''#of Samples (Groups)'''
| align="center" style="background:#f0f0f0;"|'''Requirement'''
| align="center" style="background:#f0f0f0;"|'''Test'''
|-
|rowspan="4"|Ratio or Interval(continuous/numerical)||rowspan="2"|2 || '''Normal distribution''' <br>or n>30<br>and '''Equal variances''' || Paired T test
|-
| || Wilcoxon Signed Rank test
|-
|rowspan="2" |2 || Normal distribution <br> or n>30 <br> and Equal variances  || Repeated Measures ANOVA
|-
| ||Friedman 2-Way ANOVA
|-
|rowspan="2"|Nominal (categories) ||rowspan="2"| 2 || >20 discordant pairs || McNemar's Chi Squared
|-
| || McNemar's Chi Squared<br> (Exact Method)
|}

==See Also==
*[[Statistical power]]

==External Links==


==References==
<references/>

[[Category:EBQ]]