Hello all,

I have a dataset which I am using to perform some allometric analyses. It's straightforward enough when taking the log₁₀ of single values to plot against each other, but when using the formula for Fulton's condition factor K=(M_s/L_T³)*100 where M_s is the somatic body mass and L_T is total body length, I am uncertain whether the log transformation should be done on the data being plugged into the formula or on the resulting output from the formula.

Thank you in advance.

Certainly it is suggested to plot \(y = \log(K) \) versus \( x = \log( 100M_s/L_T^3) = \log(100M_s) - 3\cdot \log(L_T). \) The reason being that the latter expression only has linear dependencies, meaning something like \(y = ax+b, \) as opposed to ratios and exponents that appear in your original. You will obtain a graphical representation which is pleasant to look at, and if you need to do a regreession analysis, these are the points you would want to do it on.