A closed-portion average does not describe the whole opening quantity

Define the quantity represented by the duration

A holding-time question needs an opening event, exit events and a stated observation unit. An average per closed unit differs from the age of units still open. Preserve those quantities rather than describing both with one unexplained average holding time label.

Keep the source’s full dates and offsets. A Canadian reporting view can display a chosen local time, but duration should come from comparable instants. A clock label crossing midnight is not enough to establish how many minutes elapsed.

Calculate an invented closed-unit weighted mean

Suppose 5 teaching units open at T. An exit of 2 units occurs 10 minutes later and an exit of 1 unit 40 minutes later. Under a quantity-weighted closed-unit model, the numerator is 2×10 + 1×40 =60 unit-minutes, divided by 3 exited units:20 minutes.

The remaining 2 units have not been assigned an exit. Dividing the same numerator by the opening 5 units would give 12 minutes, but that effectively treats the open units as if they contributed no duration to a completed statistic. It is not the declared closed-unit mean.

Report open age at a stated observation instant

At T plus 60 minutes, those 2 remaining units have an observed model age of 60 minutes from their shared opening. That is a current age, not a realised holding duration. A later exit would add new evidence and change the set of closed units.

If the opening consisted of several entries, an allocation convention is needed to connect exited units with opening instants. Do not silently apply the first entry time to every unit. A missing allocation can leave the weighted holding result unresolved.

Resolve repeated rows and different quantity units first

A duplicate representation of an exit can alter both the numerator and denominator. Preserve scoped event identifiers and source versions before averaging. Two equal quantities at equal times are not sufficient proof that two rows are duplicates.

Also keep contract counts, asset quantities and normalised exposure distinct. A quantity-weighted average is only meaningful under its stated comparable-unit model. Combining different units because their timestamps align creates another statistic that requires a separate definition.

Check chronology before weighting a duration

An exit instant earlier than its assigned opening does not become a valid duration merely because a quantity-weighted average is positive overall. Flag the inconsistent pair before aggregation. A mismatched offset, a wrong opening allocation or an unrelated event can cause such a result. Keep the original timestamps and proposed relationship visible. Do not discard the negative row or replace it with zero to make the summary appear complete.

Retain the statistic’s population and open remainder

A reproducible note reports 3 exited units, a 20-minute closed-unit mean and 2 still-open units whose age is 60 minutes at the chosen observation. Missing or corrected exit evidence should be recorded as a revision, not silently inserted into the earlier result.

All values are fictional and no actual account is queried. The duration calculation cannot establish profitability, correct execution or a suitable holding period. The optional linked crypto offer remains separate from this freely readable case study.

The optional link below leads to this site's separate crypto signals and Telegram updates offer. The record method is usable without that offer. It does not independently verify the offer, establish country eligibility or turn the teaching example into an actual transaction.

Primary sources and scope

1. RFC 3339: Internet timestamps
   Full dates and explicit numeric offsets; a timestamp representation does not prove clock synchronisation. Checked 2026-10-21.
2. Python documentation: rational arithmetic
   Exact rational calculations independently check the invented arithmetic. No account, product or strategy is authenticated. Checked 2026-10-21.