I have a spreadsheet for tracking mass shootings. I started compiling it a couple of years ago for possible use in trying to persuade my town's government to repeal a very restrictive, anti-gun town ordinance. That attempt was a total failure -- after meeting with the full governing board plus the town attorney, the result was that, according to the Mayor, "That's all very interesting, but ... wed on't like guns."
But I keep up the spreadsheet, and I now have columns for tracking Islamist terror attacks in addition to school and other mass shootings. But I'd like to figure out formulas ("formulae"?) for keeping running totals of each column, but -- for example -- not all shootings involve Islamist terror, and not all Islamist terror attacks involve shooting. I don't know how to set up a formula to add all values in Column E where the value in Column C is "Yes," but exclude values in Column E if the corresponding value in Column C is "No" or blank.
Can anyone guide me to setting this up?