Variable Probability
| Units: | % |
| Mode: | Input Only |
| Multi-band: | True |
| Default Value: | 50 |
| Validation Rule: | Any Value |
| Key Property: | No |
| Description: | Probability of exceedance (POE) |
| Detail: |
Variable Probability is the probability of exceedance (POE) of the exogenous (user-defined) sample in the given band.
Example
Assume a Variable can take one of two values, with probabilities of 80% and 20% respectively. The input for this simple case could look like the following:
| Property | Value | Units | Band |
|---|---|---|---|
| Profile | 1 | - | 1 |
| Profile | 2 | - | 2 |
| Probability | 80 | % | 1 |
| Probability | 80.01 | % | 2 |
Here the first band's value will be chosen approximately 80% of the time, whereas the band 2 value will be chosen only in the remainder of cases. Over a large sample size the average value of the sample will be 1.2.
Example
Assume now that there are three forecasts for a value given in three files with probability of exceedance of 10, 50 and 90 respectively. These can be defined as:
| Property | Value | Units | Band | Filename |
|---|---|---|---|---|
| Profile | 0 | - | 1 | HIGH.csv |
| Profile | 0 | - | 2 | MED.csv |
| Profile | 0 | - | 3 | LOW.csv |
| Probability | 10 | % | 1 | |
| Probability | 50 | % | 2 | |
| Probability | 90 | % | 3 |
See the Variable topic for more details.
Another method to define the variable [Probability] is to consider it as cumulative probability of the exogenous (user-defined) sample in the given band, by setting the undocumented parameter Stochastic_CumulativeProbability as True (See Hidden Parameter). In this method, the probabilities entered are numbers in the range of (0, 100%] and must be monotonically increasing along the bands (but not necessarily along the Profile values). The probability of the last band must be equal to 100%.
Example
To achieve the sample with the same probabilities of 80% and 20% for each band as indicated in the first example above, the input via this method should look like the following:
| Property | Value | Units | Band |
|---|---|---|---|
| Profile | 1 | - | 1 |
| Profile | 2 | - | 2 |
| Probability | 80 | % | 1 |
| Probability | 100 | % | 2 |
Example
Assume a Variable taking values from 1 to 10, with equal probability. The input via this method should be like:
| Property | Value | Units | Band |
|---|---|---|---|
| Profile | 1 | - | 1 |
| Profile | 2 | - | 2 |
| Profile | 3 | - | 3 |
| Profile | 4 | - | 4 |
| Profile | 5 | - | 5 |
| Profile | 6 | - | 6 |
| Profile | 7 | - | 7 |
| Profile | 8 | - | 8 |
| Profile | 9 | - | 9 |
| Profile | 10 | - | 10 |
| Probability | 10 | % | 1 |
| Probability | 20 | % | 2 |
| Probability | 30 | % | 3 |
| Probability | 40 | % | 4 |
| Probability | 50 | % | 5 |
| Probability | 60 | % | 6 |
| Probability | 70 | % | 7 |
| Probability | 80 | % | 8 |
| Probability | 90 | % | 9 |
| Probability | 100 | % | 10 |