Knowledge Base

Statistics for Behavior Analysis in Detail

For Continuous Sampling

For behaviors with duration only:

• Minimum duration – The shortest duration of a behavior.
• Maximum duration – The longest duration of a behavior.
• Mean duration – The total duration divided by the number of times the event occurred: D is the duration of the individual behavior, and N is the number of times the behavior occurs.
• Total duration – The sum of the duration of all events of a specific behavior.
• Standard deviation – The sample standard deviation of the duration of a behavior, where D is the duration of the individual behavior, the mean duration, and N the number of occurrences of the behavior.
• Standard error – The standard error of the mean (s.e.m.), where s is the standard deviation of a sample and N is the number of occurrences (sample size).
• Percentage – The general formula of Percentage is: Percentage = Duration of event * 100 / Duration in seconds. For Duration, you can choose between:
  • Observation duration – The total duration of the observation.
  • Interval duration – The duration of the interval specified in the data profile.
  • Analyzed observation duration – The total duration of the intervals specified in the data profile, excluding the time the observation was suspended.
  • Analyzed interval duration – The duration of the interval specified in the data profile, excluding the time the observation was suspended.
• 25th percentile – Twenty-five percent of the events of this type has this duration or lower. The 25th percentile is also called the first quartile. See Percentiles in Detail.
• Median – Fifty percent of the events of this type have this duration or lower. The Median is the same as the 50th percentile or 2nd quartile. See Percentiles in Detail.
• 75th percentile – Seventy-five percent of the events of this type have this duration or lower. The 75th percentile is also called the 3rd quartile. See Percentiles in Detail.

For all behaviors:

• Rate per minute (RPM) – The general formula of Rate per minute is: Rate per minute = (Total number of occurrences / Duration in seconds) * 60. For Duration, you can choose between:
  • Observation duration – The total duration of the observation.
  • Interval duration – The duration of the interval specified in the data profile.
  • Analyzed observation duration – The total duration of the intervals specified in the data profile, excluding the time the observation was suspended.
  • Analyzed interval duration – The duration of the interval specified in the data profile, excluding the time the observation was suspended.
• Total number – The number of times the selected event occurs in the observation or event log.
• Latency – The time from the start of the observation to the first occurrence of a behavior. When you have created intervals based on data selection, the latency is only calculated for the behavior within one of the intervals.

Note: To calculate the time between a behavior and the moment another behavior starts, do not use Latency. Latency is always calculated from the start of the observation. Instead, select Intervals by Manual Selection and calculate the interval duration. For example, to find the time between the moment the mother leaves the room and the baby first starts crying, create an interval by manual selection with the start and stop criteria both based on observational data. Carry out a behavior analysis and from the statistics select Analyzed Interval Duration. In the Layout window, select the checkbox in front of Intervals. See Group Elements.

Percentiles in Detail

In this example, 25% of the events scored has a duration of 2 s or lower. 50% of the events has a duration of 3 s or lower. The 50th percentile is the Median. 75% of the events has a duration of 4 s or lower.

The event Play was scored eight times. When the duration of the events is sorted, the Median (50th percentile) divides the scored events equally. In this example it lies halfway between 4 and 5 s, which is 4.5. Fifty percent of the events, which is four events, has a duration of 4.5 s or lower.

Statistics for Instantaneous Sampling

• Proportion (All Samples) – The number of times a behavior has been scored divided by the total number of samples in the observation.
• Proportion (Scored Samples) – The number of times a behavior has been scored divided by the number of scored samples.
• Scored Samples – The number of times a behavior has been scored in an observation.
• Total Number (All Samples) – The total number of samples in an observation.
• Total Number (Scored Samples) – The total number of scored samples.

Example: A group of 10 animals is observed during an hour with a sample interval length of 5 minutes. The Total number (all samples) is 12. For a specific animal, 4 samples are missing. Total number (scored samples) for this animal is 8. For this animal behavior 'Sit' has been scored '4' times. Scored samples for Sit is 4. Proportion (all samples) = 4/12 = 0.33. Proportion (scored samples) = 4/8 = 0.50.

Statistics for Intervals

• Minimum Interval – The shortest interval duration.
• Maximum Interval – The longest interval duration.
• Number of Intervals – The total number of intervals.
• Interval Duration – The duration of each interval.
• Total Interval Duration – The duration of all intervals together.
• Analyzed Interval Duration – The interval duration minus the time that the observation was suspended within this interval. Make sure Intervals is selected in the layout window.
• Analyzed Duration – The sum of the intervals minus the time that the observation was suspended within the intervals.

Notes on Intervals or Time Bins

When one event overlaps two or more intervals, it is counted one time in each interval. The Total number statistic is the number of times an event occurs within an interval or time bin. This means that when you define intervals or time bins, the Total number statistic may be larger than the true number of occurrences of that event.