From this list you can select a variable by clicking on the variable's name. 

If the variable requires a logarithmic or square root, or any other mathematical transformation, then you 

can enter a formula in the variable field: 

 SQRT(WEIGHT) 

 LOG(LENGTH) 

or you can enter a formula combining different variables, e.g. 

 WEIGHT/LENGTH 

By doing so, new variables will be added to the variables list: SQRT(WEIGHT), WEIGHT/LENGTH, etc.. 

For an overview of mathematical operators and functions available in MedCalc, refer to pages 155 and 

156.  

Optionally, you may also enter a selection criterion in the Select field of the dialog box, in order to include 

only a selected subgroup of cases in the statistical analysis. 

The Select field may contain a combination of different criteria, using the AND and OR functions (see also 

p. 162): 

 AND(LENGTH>160,LENGTH<170) 

These expressions may make use of all mathematical and other spreadsheet functions as described in a 

next part of this manual (p. 155). 

After you have entered a selection criterion in a dialog box (in order to include only a selected subgroup of 

cases in the statistical analysis), this selection criterion will be `remembered' by the program and will be 

selectable in the Select list. 

After you have selected the 

OK

 button, the following statistics are calculated and displayed in the results 

window: 

8