Statistics for the Terrified: Glossary
Click on an item below to see the definition
Non-parametric statistics:
That branch of statistics concerned with tests that make no assumptions
about the distribution of the data - for this reason also called distribution-free statistics. Because there
is no distribution, there are no parameters to estimate. The Mann-Whitney and Wilcoxon tests are examples.
See also Parametric statistics.
Normal distribution:
The most common distribution, when
extreme values are much less likely to occur than the values in the middle. This
distribution is symmetrical about the mean and has a bell shape. Height and weight
are good examples of variables that are normally distributed. Many naturally
occurring physical measurements follow the normal distribution, which was discovered
by the German philosopher Gauss.
See also Distribution.
Null distribution:
The distribution of the test statistic when the null hypothesis is true.
See also Distribution, Null hypothesis.
Null hypothesis (h0):
The null hypothesis is an aunt sally put forward to be disproved, usually
stating that there is no difference or relationship between the items under study.
See also Null distribution.
