Help with IF formula that references cells that contain validated data from a drop-down

So I am unable to upload a copy of what I have because of the sensitivity of the data but it is pretty simple to explain. I am using a current attendance spreadsheet that has drop-down lists (with validated data) to identify whether a student is absent, present, half day absent, or a bunch of other reason codes such as A20. There are some characters which are not on the keyboard, such as a check mark, which represents that a student was present that entire day. As it stands now there is a row at the right side of each month where you need to manually count the number of days present or absent etc. What I need, however, is to be able to create a formula that will check each cell for a specific date range (which I specify--and change if needed) and will count the number of days present and add them. So for example if it detects the check mark it should count this as 1 day present, if it detects the check mark with 1/2 next to it it will count that as .5, and any other option but those two will return a value of 0. I need to be able to tell at any given time for each student for any specific period of time how many days they were present and how many days they were absent and then I will plug those into a final formula that will give me the percentage of attendance for a specified time frame. I have started playing around with it but when I reference those cells that contain the validated data it throws a Name! error. Thank you so much for any help as I am not great at formulas yet!!