Estimating the logistic parameters

Linear models are fitted to data by selecting the values of the two parameters b0 and b1 to minimise the sum of squares of residuals, but the parameters b0 and b1 of a logistic model cannot be found as easily.

Model-fitting for proportions is based on a method called maximum likelihood that is beyond the scope of CAST, but many statistical programs will find maximum likelihood estimates, so we take a 'black box' approach and simply show the best-fitting logistic curve in the example below.

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