Xero C1 Pro Chronograph Standard Deviation Calculation

How is the standard deviation calculated on the Xero® C1 Pro Chronograph?

There are two main formulas to calculate standard deviation; population and sample.

• The population formula reports the standard deviation of an entire population of data, not just a subset.
• The sample formula is very similar to the population formula, but takes into account that the data that is being provided to the formula is only a sample or subset of the larger population of data.
  • Therefore, the values returned from the sample formula are typically larger than the values returned from the population formula, to account for variability in the larger dataset.

The Garmin Xero C1 Pro Chronograph uses the Standard Deviation Population formula to calculate the standard deviation of a session because it’s only reporting the data about the current session, not trying to make assumptions about a larger dataset.

For most applications, including reloading, as long as the numbers being compared across datasets (loads in the reloading case) utilize the same formula, there is no advantage to one or the other.

The standard deviation sample data is still available if the user exports their data from the ShotView app and uses the STDEV.S formula in spreadsheets.