List of Group statistics
Aim
Group statistics are a summary of trials in a specific experimental group. Here a “group” refers to the tracks selected in a Result box in the Data profile. See Define groups of tracks
Choose between Group mean and 5 number summary.
note Group statistics are not available when you only select Standard deviation, Standard error or Variance as Trial statistics.
▪For most variables, including Turn angle, Angular Velocity and Meander, the Group mean is the arithmetic mean of the trial statistics, calculated for each group.
▪For the variables Heading, Head direction, and Heading to Point, the group mean is calculated as the circular mean, with N being the number of trials in the group.
If you select Group mean, the following options are available:
▪Standard Deviation. For most variables, the sample standard deviation of the trial statistics, calculated for each group. For the variables Heading, Head direction, and Heading to Point, the group standard deviation is calculated as the circular standard deviation (see above), with N being the number of trials in the group.
▪Standard Error. The Standard deviation divided by the square root of the number of tracks used to calculate the Standard deviation. This is also the case for angular variables Heading, Head direction, and Heading to Point.
This is the Minimum, the Lower quartile, the Median, the Upper quartile and the Maximum value of trial statistics calculated for each group.
The method used to calculate quartiles is the N + 1 Basis interpolation, which is also used in SPSS. If the sample size is lower than 3, the lower quartile is the same as the minimum and the upper quartile is the same as the maximum value, which is also the same as in SPSS.
note With 5 number summary you can also plot data in form of Box and whiskers charts. You can also show the original data points for better interpretation. See Group charts > Customize the group charts
See also