# NMath User's Guide

43.6 Predicted Probabilities (.NET, C#, CSharp, VB, Visual Basic, F#)

You can use a LogisticRegression object to generate predictions. The PredictedProbability() method returns the probability of a positive outcome predicted by the model for a given set of predictor values. For example:

Code Example – C# logistic regression

``` var predictors =
```
```  new DoubleVector( 150.0, 33.5, 0.66, 80.0 );
```
```double predicted = lr.PredictedProbability( predictors );
```

Code Example – VB logistic regression

```Dim Predictors As New DoubleVector(150.0, 33.5, 0.66, 80.0)
```
```Dim Predicted As Double = LR.PredictedProbability(Predictors)
```

A MismatchedSizeException is raised if the length of the given vector is not equal to the number of parameters in the model.

Similarly, the PredictedProbabilities() method returns a vector of predicted probabilities of a positive outcome for the predictor variable values contained in the rows of an input matrix.

Code Example – C# logistic regression

```var predictors =
```
```  new DoubleMatrix( "3x4 [ 150.0 33.5 0.66 80.0
```
```                           160.0 24.5 0.88 70.0
```
```                           170.0 22.6 0.56 60.0 ]" );
```
```DoubleVector predicted = lr.PredictedProbabilities( predictors );
```

Code Example – VB logistic regression

```Dim Predictors As New DoubleMatrix("3x4 [ 150.0 33.5 0.66 80.0
```
```                                          160.0 24.5 0.88 70.0
```
```                                          170.0 22.6 0.56 60.0 ]")
```
```Dim Predicted As DoubleVector =
```
```  LR.PredictedProbabilities(Predictors)
```

In the returned vector of predicted observations, the ith element is the predicted response for the set of predictor variable values in the ith row of the given matrix.

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