Script to count fields populated with a certain value & place that total in a numeric field

Please, I need a script to count text fields populated with a certain value chosen from a drop down menu and place that total in a numeric field. An instance is below:

Passive 2           Dropdown List  Passive

                          Dropdown List  Passive

Active   1            Dropdown List  Active

I've seen similar questions and responses to this inquiry and I've tried to add the script with my values but I'm not having any luck

Thanks,