

Prism can easily perform a ratio t test from two columns of data entered into a Column data table.
1.Create a column data table and enter two columns of data, with matched values on the same row. For example:
Control 
Treated 
4.2 
8.7 
2.5 
4.9 
6.5 
13.1 
2.From the data table, click on the toolbar.
3.Choose t tests from the list of column analyses.
4.On the first (Experimental Design) tab of t test dialog, make these choices:
•Experimental design: Paired
•Assume Gaussian distribution: Yes. (Actually you are assuming a lognormal distribution of differences.)
•Choose test: Ratio paired t test
5.On the second tab of the t test dialog, choose to compute Treated  Control, rather than Control  Treated. Note that even though the ratio t test computes a ratio, the choice on the dialog is worded as if the values were subtracted.