Performs a one- or two-sample t-test. The menu carries out validity checks. If
any sample has fewer than 6 values, a warning is given that the sample size is
too small and the test may not be valid. Also, in the two-sample (unpaired)
case, an F-test for equality of variance is carried out and a warning printed
if there is evidence of unequal variances. For a two-sample unpaired t-test you
can also choose to calculate the probability using a random permutation test. Weights
can be supplied to replicate observations within the
options dialog.
Test
Specifies the test to be carried out: One-sample, Two-sample (unpaired), or
Two-sample (paired).
Data Arrangement
For a Two-sample (unpaired) test the data can be supplied either as a pair of
variates or as a single variate with a factor defining the groups.
Two Sets
The samples must be supplied as two separate variates, whose names should be
entered as Data Set 1 and Data Set 2.
One Set with Groups
The data must be supplied in one variate, specified as the Data Set. Membership
of the two samples is then indicated by a factor whose name should be entered
in Groups.
Confidence Limit
Allows you to control the limit for the calculation of a confidence interval.
The limit is expressed as a percentage and must be in the range 0-100
Type of Test
Allows you to choose either a one-sided or two-sided t-test.
Available Data
List variates and factors that can be used to supply the data sets and/or
groups. The contents may change as you move from one input field to another,
so that appropriate types of data structure are listed. Double-click on a name
to copy it into the current input filed; alternatively you can enter the name
directly using the keyboard.
See Also