What is 'F software'?

Am so sorry it mean free software for epidemiology

There might be no "best" software overall, the answer will depend on your needs and skills. For my own purpose I find "R" very usefull. You can download R at

http://cran.r-project.org/index.html

A free handbook explaining the use of R for epi applications is available at

http://cran.r-project.org/doc/contrib/Epicalc_Book.pdf

Olaf Berke thank you so much

For basic and intermediate epidemiological analysis, EpiInfo is enough, and much friendlier than R. It is also good for data entry and for building maps. For complex statistics or complex data handling R is far better.

EpiInfo is the best software commonly used by epidemiologist. As Cesar Carcamo suggested, it is simple to use with high accuracy.

STATA is also a user friendly software and a trial version is also available for "F"

I dito R. If you're new to R try it with R Studio and install the package R commander, this gives you an environment similar to SPSS or STATA and is much more userfriendly. (I assume here that you might not be too keen on command line programming in the first instance.)

Epi INFO and R

I reckon R studio. which  is an amazing software that you should use for F if F stands for free.  get the free  access at 

https://www.rstudio.com/products/rstudio/download/

cheers!

nice information