Standard error of estimate (Se)
The coefficient of determination r^{2} gives us an indication of the reliability of the estimate of total cost based on the regression equation but it does not give us an indication of the absolute size of the probable deviations from the line established. This information can be obtained by calculating the standard error of estimate given by the following formula.
For computation purpose,
Where k is the no. of independent variables
The calculation of the standard error is necessary because the least square line was calculated from sample data. The other samples would most likely outcome in different estimates. Obtaining the least square calculation over all the possible observations that might occur would result in the calculation of the true least square line. The question is “How near does the sample estimate of least square line come to the accurate least square line.