Age when girls menstruate

Use this diagram to introduce the idea of estimating the parameters to get the logistic curve 'close' to the data.

Drag the two red arrows to change the logistic curve's parameters.

Click Best fit to show the best (maximum likelihood) estimates. State that a computer will find the best estimates but the underlying details are fairly advanced.

A study was conducted in Warsaw to determine the proportions of girls who had started menstruating at different ages. A total of 3898 girls of various ages between 8 and 19 were asked whether they had started menstruating.