Docstoc

Probability

Document Sample
Probability Powered By Docstoc
					CHI-SQUARE GOODNESS OF FIT TEST
               What Are
        Nonparametric Statistics?
• Statistical tests such as the t-test and z-test
  are parametric because they test a hypothesis
  about a particular population value
  (parameter).
• Nonparametrics such as chi-square test a
  hypothesis, but not about one particular
  parameter.
              What Are
        Nonparametric Statistics?
• Parametric statistics require assumptions that
  are often not satisfied (e.g., shape of the
  population distribution, interval/ratio data).
• Nonparametric statistics require assumptions,
  but they are easier to meet.
What is the Purpose of the Chi-Square
          Goodness of Fit?
• Test whether an observed frequency
  distribution differs from a Null Hypothesis
  frequency distribution.
• Use for a design in which individuals
  categorized into two or more groups.
     What are the Assumptions?
• mutually exclusive groups
• expected frequencies at least 5 per cell
         How Does it Work?

• Determine the frequencies you expect if
  the Ho is true.
• Compare the observed frequencies to the
  Ho expected frequencies.
• Large differences between observed and
  expected give a large value of chi-square,
  likely to be significant.

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:0
posted:5/17/2012
language:
pages:6