THE NUMBERS, EXPLAINED
How to use this calculator.
Inputs are nonnegative day differences calculated on a consistent date basis. Describes completed observations only.
Start with your inputs
Enter booking lead times for service a (days), booking lead times for service b (days). Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Booking lead times for service A (days) | 2,4,6 |
| Booking lead times for service B (days) | 7,14,21 |
A worked example
With the example inputs above, service a mean lead time (days) is 4. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Service A mean lead time (days) | 4 |
| Service B mean lead time (days) | 14 |
| Combined mean lead time (days) | 9 |
| Shortest and longest lead time (days) | 2, 21 |
How this is calculated
Service A mean lead time (days)
Average days between booking and appointment for service A.
Service B mean lead time (days)
Average observed lead times for service B.
Combined mean lead time (days)
Weight service means by their booking counts.
Shortest and longest lead time (days)
Report the observed combined range.
Symbols and units
- a
- Booking lead times for service A (days)
- b
- Booking lead times for service B (days)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions and limits
Inputs are nonnegative day differences calculated on a consistent date basis. Describes completed observations only.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
Service A mean lead time (days); Service B mean lead time (days); Combined mean lead time (days); Shortest and longest lead time (days). The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: Inputs are nonnegative day differences calculated on a consistent date basis. Describes completed observations only.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Further reading
OpenStax: Measures of the Center of the Data ↗
Background reading; this does not imply endorsement or independent review of SumFizz.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
Read the quality report →