Data parameters can now support grouped data.

$g=data(10~20:2,20~30:6,30~40:4,40~50:2)

This data parameter is equivalent to this frequency table.

Each entry in the data parameter is the group definition, separated by a ~, and the frequency, separated by a :.

Statistical Calculator Commands

All statistical commands honour the group and frequency information. For example {mean($g)} will return 29.28

Grouped Data Calculator Commands

The definition of $g creates 4 group entries. If you reference one of the entries, $g[3] for example, you will see 30~40:4. There are two commands which allow you to access the group definition and the frequency of the entry.

{groupdefn($g[3])} will return 30~40
{freq($g[3])} will return 4

Grouping Existing Data

If you have a parameter which contains raw, ungrouped data you can group it using a calculator command.

For example. If

$p=randnormal(50,15,30)

{group($p)} will return the raw data automatically grouped.

Often, the best way to use the group command is within parameter definitions.

$p=randnormal(50,15,30)
$g=group($p)

This will create a set of randomly generated grouped data, perfect for histogram type questions.