A frequency distribution shows the number of data values in each of several nonoverlapping classes.Statistics offers methods to estimate and correct for any bias within the sample and data collection procedures.For this reason, there is no way to immediately infer the existence of a causal relationship between the two variables.

One approach that does yield an interval that can be interpreted as having a given probability of containing the true value is to use a credible interval from Bayesian statistics : this approach depends on a different way of interpreting what is meant by "probability".Statistical inference, however, moves in the opposite direction inductively inferring from samples to the parameters of a larger or total population.

This still leaves the question of how to obtain estimators in a given situation and carry the computation, several methods have been proposed: the method of moments, the maximum likelihood method, the least squares method and the more recent method of estimating equations.Trends, Ecology and Evolution (21) 296:302 Gayon,.Measurement theory and practice: The world through quantification.