In
statistics, a
studentized residual is the quotient resulting from the division of a
residual by an
estimate of its
standard deviation. Typically the standard deviations of residuals in a sample vary greatly from one
data point to another even when the
errors all have the same standard deviation, particularly in
regression analysis; thus it does not make sense to compare residuals at different data points without first studentizing. It is a form of a
Student's t-statistic, with the estimate of error varying between points.