Question

What level of measurement must the days be in order to perform the least squares regression analysis?

Answer 1

All arithmetic operations are possible on a ratio variable.Additionally, ratio variables have a meaningful zero-point (e.g., exactly 0 pounds means the object has no weight).A ratio variable can be used as a dependent variable for most parametric statistical tests such as t-tests, F-tests, correlation, and regression.

For interval variables, we can make arithmetic assumptions about the degree of difference between values. An interval variable can be used to compute commonly used statistical measures such as the average (mean), standard deviation, and the Pearson correlation coefficient. Many other advanced statistical tests and techniques also require interval or ratio data.

Hence the days must be in Interval scale data levels of measurement or Ratio scale data levels of measurement in order to perform the least squares regression analysis.