Data Table, Equation Fit or Interpolation

The results of an experiment can be presented as a data table or as an equation that represents them. In the case of adjusting a polynomial, Excel allows us to change its degree and calculates the R2 of the adjusted equation. It is considered that if it is 1 the equation goes through all the experimental points. By adjusting Tungsten resistivity data, it is found that the equations do not go through all the points (even with R2 = 1), which is verified by calculating the differences for each point. In those cases, the best fit is the linear interpolation between consecutive points. The equation adjusted by Excel, Matlab or Origin requires checking if it corresponds to the minimum in the sum of squared differences, it is possible that it can be reduced by changing the coefficients values.