physical chemistry - How to determine the empirical formula for an unknown iron oxide?

I have to determine the empirical formula of an oxide of iron which has $69.9\%$ iron and $30.1\%$ dioxygen by mass in it.

I have started as follows:

1. 
   

   For our convenience we take $\pu{100 g}$ of that iron oxide:
   We have $\pu{69.9 g}$ of iron in it and $\pu{30.1 g}$ dioxygen in it.

   
   
   


2. 
   

   We convert into amount of substance of each element:

   
   
   
   
   • $\text{amount of substance of iron} = 69.9/55.8 = 1.25$
   
   
   • $\text{amount of substance of dioxygen} = 30.1/32 = 0.94$
   
   
   
   

Is my method and calculations right?