I want to write "conditional (mean imputation)" and "unconditional (mean imputation)" shorter, which of these 4 is the best way to do that? If multiple ways are correct, which is the most common (in American English)?
- (un)conditional or
- (un-)conditional or
- (un) conditional or
- (un-) conditional
Which way of writing is correct; and
Edit: for clarification: In statistics there exists "conditional mean imputation" and "unconditional mean imputation" (see e.g. p. 225 in "Linear Mixed Models for Longitudinal Data" by Verbeke and Molenberghs: which I want to shorten to "(un)conditional mean imputation".
One example sentence is
There are many diverse imputation methods: in (un)conditional mean imputation, missing values are replaced by the (un)conditional mean. In regression based imputation, missing values... In hot deck imputation...".
Writing only "mean imputation" is not an option, as I want to make clear that there are two distinct mean imputation methods.