The pre-defined Gaussian fitting function in the Curve Fitting App is defined slightly differently than the probability distribution function of a Gaussian random variable. Since the "Results" pane in the Curve Fitting App only displays the values of the model parameters, it is not possible to have the App display the standard deviation of the Gaussian function as it is typically defined. Moreover, the std function is not defined for cfit objects since this has no logical meaning for most models, so calling std on the exported model yields an error.
As a workaround, you can define a Custom Equation as the model type and supply the statistical definition of a Gaussian function, using the standard deviation as its own parameter. The fit will then display the value of the standard deviation in the "Results" pane.
Alternatively, instead of fitting a Gaussian function to the histogram data, you can use the
directly on the original data. This will allow you to fit a Normal distribution to the data and will display its mean and variance. You can then export the distribution to the workspace and call the std function on the distribution. This will return the standard deviation of the fitted probability distribution.
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