Statistics can be created for files, compensated files, and gates. To create a statistic, select the Statistic button from the side panel. There are several different statistics that can be added. If statistics are added to compensated files, the stat is calculated after compensation is applied.
Calculated by adding the values of all events for a parameter and diving by the total number of events.
Equivalent to taking 50th percentile.
Standard Deviation - Calculated by first finding the mean for all the events for a parameter. Then for each event, we find the square of its distance to the mean and sum them. Then we divide by the the total number of events and take the square root.
Coefficient of Variation - the ratio between the standard deviation and mean.
Pearson Correlation Coefficient for two parameters. Calculated with the following:
r = Σ(xᵢ - x̄)(yᵢ - ȳ) / sqrt(Σ(xᵢ - x̄)² * Σ(yᵢ - ȳ)²)
- xᵢ = values of first parameter
- x̄ = mean value of first parameter
- yᵢ = values of second parameter
- ȳ = mean value of second parameter
The number of events that are contained within the population.
The concentration of the population in cells/milliliter. In order to use this statistic your FCS file must contain the $VOL keyword, which provides the amount of volume in the sample run. If your file doesn't have this keyword, the "Concentration" option will be greyed out. Note that although the FCS3.1 specification mandates that this value be in nanoliters, some cytometers completely ignore this and use other units, most often microliters. If your FCS files are non compliant with the specification, concentration statistics will be incorrect.
The minimum value within the population.
The maximum value within the population.
Calculated by taking the number of events in a population divided by the number of events in the file.
Calculated by taking the number of events in a population divided by the number of events in its parent. If this stat is applied to a population without a parent (a file for instance), the percent will be 100%.
The value below which a certain percentage of events (cells) in a dataset would be found.
Every FCS file has a bunch of included keywords. These are key:value pairs that give information about the name of the file, the parameters, the cytometer, and a bunch more information about the data. Using the Keyword statistic you can show the value of a particular keyword.
Allows you to attach a label with a custom value of your choosing to a population.
Statistics can be deleted by right clicking them in the file tree and selecting "Delete".
Statistics can be dragged and dropped onto other files, compensated files, or gates.
When you create a new stat, you have the option to input a custom display name if you so choose. You can also rename the stat at any time by right clicking its entry in the file tree and selecting "Rename". Providing a custom display name for a statistic may be useful if the fully qualified name of the stat is very long because of a very nested gating tree, which can be difficult to work with when exported as a CSV file (See next section).
Statistics can be exported to a CSV file which can be opened in any spreadsheet-type application (Excel) for further analysis. To export stats, click "File" then "Save CSV Statistic File". When exported, all statistics from all open files in the current project will be tabulated.
Statistics will be shown in the CSV file using a fully qualified path (i.e. [File]/[Gate]/[Gate]/[Stat]). If you have a very nested gating hierarchy this can be difficult to work with. If you have assigned a custom name to the statistic, both the custom name and the full name will be exported and can make further analysis a little easier.