• Refers to the use of statistical tests or methods when the data being studied comes from a sample or population of people that is normally distributed.

• Assumes patient population being studied is normally distributed
• Assumes the variance is homogeneous
• Type of data: interval or ratio.  Sometimes referred to as continuous variables/data.
• Interval scale data:
• When numbers have units that are of equal magnitude as well as rank order on a scale without an absolute zero
• Ratio scale data:
• When numbers have units that are of equal magnitude as well as rank order on a scale with an absolute zero
• The usual central measure is a mean

• T-test (assumes 2 independent groups (i.e., not related) being studied)
• One-way ANOVA (assumes > 2 independent groups being studied/compared)
  
• Pearson (correlation test)

• T-Test
• One-way ANOVA
• Nonparametric Statistical Analysis
  

1. Gaddis ML et al. Introduction to biostatistics: part 1, basic concepts. Ann Emerg Med 1990;19:86-89.
   

Editors:

• Anthony J. Busti, MD, PharmD, FNLA, FAHA
  

Last Reviewed: July 2015