# Group Statistics result

Aim

The Group Statistics & Charts tab shows the statistics for the groups of trials defined in your Data Profile.

▪In the Group Statistics result table, each group is labeled as the corresponding Result container in the Data profile. The statistics are calculated for the trials/arenas/subjects included in that Result container. For how to group data, see Analyze groups of tracks.

▪The dependent variables (e.g. velocity) are those specified in the currently-selected Analysis profile.

note If you use the default Data profile, all trials are grouped. The Group Statistics & Charts table shows the statistics for all trials together.

Procedure

Choose Analysis > Results > Statistics and Charts and click the Group Statistics & Charts tab.

Example

In the following example, the Data profile includes two Result containers: Result 1 for treated subjects, Result 2 for control subjects. The groups have been created with Filter boxes, each selecting a value of the independent variable Treatment, Control or Treated. Each Result Container contains two tracks.

The Group Statistics table looks like this:

The statistics are displayed for each Result container. Result 1 contains the tracks marked as Treated; Result 2 contains the tracks marked as Control.

In addition, a chart is created automatically for each dependent variable in the table. See Group charts

How to read the Group statistics

▪Statistics should be read as follows: [Lower level header] of [Higher level header] is [value in cell]. For example:

415.3275 cm is the Mean of the per-trial Total Distance moved for the tracks contained in Result 1.

▪N is the number of tracks used to calculate the group statistic for that dependent variable.

▪Group statistics are split in multiple rows when you define results per time bin and/or zone. In the example below, results are split per zone defined in the Data profile, under Results per zone. See Calculate the results per zone

▪By default, user-defined independent variables are displayed in the table. To show more independent variables, click the Show/Hide button and choose Independent Variables.

▪If tracks in a group have different values of an independent variable, the text [multiple values] is displayed for that group:

How group statistics are calculated

For most dependent variables, The group Mean is the arithmetic mean of the values of the dependent variable reported in Trial Statistics. For angle variables like Heading, Heading to point, and Head direction, (but not for Turn angle) the circular statistics are used.

Group statistics are not weighted. For example The total distance moved is 100 cm for trial 1, and 200 cm for trial 2. The resulting group mean is 150, independent of how many samples each track is made of.

Similarly, the group Standard error, Standard deviation, and the 5-number summary (Minimum, First Quartile, Median, Third Quartile and Maximum) are calculated from the single values of the dependent variables reported in Trial Statistics.

Notes

▪The number of decimals in the Trial Statistics and Group Statistics is fixed to four. When exporting the results table, the number of decimals varies depending on the number of integers in the value. See Export the statistics result

▪The dependent variables displayed in Group Statistics & Charts are those defined in the Analysis profile chosen from the list in the toolbar.

▪The statistics displayed in Group Statistics & Charts are those selected under Group Statistics for that variable in the currently active Analysis profile. Group statistics are always measures of central tendency, either a Mean (with Standard deviation and/or Standard error) or the 5-number summary (Minimum, First Quartile, Median, Third Quartile and Maximum). You cannot calculate, for example, the group total of distance moved.

▪The group statistics can be calculated for all the trial statistics, except for the standard error, the standard deviation and the variance. For example, you cannot calculate the group mean of the trials’ standard deviations of a variable.

▪To add and remove statistics, right-click any column header for the dependent variable for which you want to add or remove the statistics, and select Properties. On the Trial Statistics and Group Statistics tabs, select the statistics that you require.

▪See also Analyze groups of tracks.