Question

Define what Goodness of Fit is, briefly discuss the objective of testing for Goodness of Fit in a minimum of a paragraph

Answer 1

Goodness-of-fit, in general, refers to measuring how well do the observed data correspond to the fitted model.

The idea is that if the observed frequency is really close to the expected frequency, then the square of the deviations will be small. The square of the deviation is divided by the expected frequency to weight frequencies. If the sum of these weighted squared deviations is small, the observed frequencies are close to expected frequencies and the model is OK. Only when the sum is large is the a reason to question the distribution.