# Probability

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```					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
(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.
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.

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 views: 0 posted: 5/17/2012 language: pages: 6