Variable Probability

Units:%
Mode:Input Only
Multi-band:True
Default Value:50
Validation Rule:Any Value
Key Property:No
Description:Probability of exceedance (POE)

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