Some data is linearly additive, other data is not. In this paper, I discuss types of data based on the boundedness of the data and their linearity. 1) Unbounded data can be linear. 2) One-side bounded data is usually log transformed to be linear. 3) Two-side bounded data is not linear. 4) Untidy data do not fit in these categories. An example of two-sided bounded data is probabilities which should be transformed into a linear probability space by taking the logarithm of the odds ratio (log10 odds) which is termed Weight (W). Calculations of means and standard deviation is more accurate when calculated as W values than when calculated as probabilities. A methods to analyze untidy data is discussed.