Knowledge Base

Data Analysis (Continued)

Values (Average proximity; see Figure 9 in the original paper).

In EthoVision XT

In the Analysis profile, choose the dependent variable Distance to zone, with the Statistic Mean. This equals the Gallagher's Average search error in all cases.

Data Correction

For both probe trials and training trials, Gallagher et al. (1993) made a correction so that trial performance was relatively unbiased by differences in distance to the goal from the various start locations at the perimeter of the pool (see page 621 in the paper).

If you want to apply this correction to your data:

1. Measure the distance D between the release point and the platform. In the EthoVision XT Trial List, define an independent variable D and for each trial enter the appropriate value depending on the release point used in that trial. Values will be used later in the Excel export file.
2. In the Analysis profile, define the dependent variables Distance to zone, In zone (not in platform) and Velocity.
3. Choose Analysis > Export > Raw Data and choose Excel as File type.
4. In Excel, create macros/formulas that calculate (see the next page):
   • The average velocity v when In zone = 1.
   • The time needed to reach the platform from that starting point: t = D/v.
   • Insert a new column Valid time, assign the value 1 if Recording time in the same line is higher than t.
   • Calculate the average distance to zone (platform) for when In zone = 1 and Valid time = 1 (use the Excel function averageifs).
   • Calculate the total distance to platform when In zone = 1 and Valid time = 1 (use the Excel function sumifs).

Source: EthoVision XT 18 - Application Manual, Noldus Information Technology