I need some advice, What could it possibly mean, in an article I am studying, where the results of a test (visual-spatial working memory) in relation to a variable (Maths skills in kids) is being discussed as follows: "The distribution of the variable was so negatively skewed, that it was reversed and then logarithm was used to enable parametric tests" Of course these are in my own words (I´m reading in finnish), but I don´t think I have left anything important out. So I know what skewness and logarithm are, but I am puzzled about the reversing? Why would you reverse a distribution? To enable parametric tests? Why?