Declares one or more variate data structures.
Options
NVALUES = scalar or vector |
Number of units, or vector of labels; default * takes the setting from the preceding UNITS statement, if any |
|---|---|
VALUES = numbers |
Values for all the variates; default * |
MODIFY = string token |
Whether to modify (instead of redefining) existing structures (yes, no); default no |
IPRINT = string tokens |
Information to be used by default to identify the variates in output (identifier, extra); if this is not set, they will be identified in the standard way for each type of output |
Parameters
IDENTIFIER = identifiers |
Identifiers of the variates |
|---|---|
VALUES = identifiers |
Values for each variate |
DECIMALS = scalars |
Number of decimal places for output |
EXTRA = texts |
Extra text associated with each identifier |
MINIMUM = scalars |
Minimum value for the contents of each structure |
MAXIMUM = scalars |
Maximum value for the contents of each structure |
DREPRESENTATION = scalars or texts |
Default format to use when the contents represent dates and times |
Description
The variate is probably the structure that you will use most often in Genstat. You can think of this as being just a list of numbers – a vector, in mathematical language. Variates occur for example as the response and explanatory variables in regression, as covariates and y-variables in analysis of variance, and can be used to form the matrices of correlations, similarities or sums of squares and products required for multivariate analyses.
The IDENTIFIER parameter lists the variates that are to be declared. Values can be assigned by either the VALUES option or the VALUES parameter. The option defines a common value for all the variates in the declaration, while the parameter allows them each to be given a different value. If both the option and the parameter are specified, the parameter takes precedence.
The NVALUES option allows the number of values in the variates to be defined. If this is not set, the lengths of the variates are defined from the numbers that are supplied by the VALUES option or parameter. If these too are unset, Genstat takes the length specified by the preceding UNITS statement, if any.
The DECIMALS parameter allows you to define a number of decimal places to be used by default when each variate is printed. You can associate a text of extra annotation with each variate using the EXTRA parameter. The MINIMUM and MAXIMUM parameters allow you to define lower and upper limits on the values in each variate. Genstat then prints warnings if any values outside that range are allocated to the variate. The DREPRESENTATION parameter allows a scalar or a single-valued text to be specified for each variate to indicate that the variate stores dates and times, and to define a format to be used for these, by default, when they are printed; details are given in the description of the PRINT directive.
If the MODIFY option is set to yes any existing attributes and values of the variates are retained (if still appropriate); otherwise these are lost. The IPRINT option can be set to specify how the variates will be identified in output. If IPRINT is not set, they will be identified in whatever way is usual for the section of output concerned. For example, the PRINT directive generally uses their identifiers (although this can be changed using the IPRINT option of PRINT itself), while the ANOVA directive will print the identifier and the extra text for each y-variate.
Options: NVALUES, VALUES, MODIFY, IPRINT.
Parameters: IDENTIFIER, VALUES, DECIMALS, EXTRA, MINIMUM, MAXIMUM, DREPRESENTATION.
See also
Directives: FACTOR, TEXT, UNITS.
Procedure: TX2VARIATE.
Commands for: Data structures.
Example
" Example 2:2.2.3 " " A scatter plot is drawn of blood-pressure against age for 38 women. Then two rugplots are added to show the distribution of ages and pressures along the axes." VARIATE [VALUES=82.17,88.19,89.66,81.45,85.16,89.77,89.11,107.96,\ 74.82,83.98,92.95,79.51,87.86,76.85,76.93,87.09,97.55,92.04,100.85,\ 96.30,86.42,94.16,78.12,89.06,94.58,103.48,81.30,83.71,68.38,86.64,\ 87.91,86.42,103.87,83.76,84.35,68.64,100.50,100.42] Pressure VARIATE [VALUES=28,46,63,36,42,59,54,77,21,57,47,34,51,27,24,41,66,\ 69,72,60,50,57,32,59,74,77,41,36,20,47,51,57,69,36,54,24,61,80] Age DGRAPH Pressure; Age RUGPLOT [SCREEN=keep] Pressure RUGPLOT [SCREEN=keep; ORIENTATION=across] Age