If, say, 95% of people tend to eat less sweets when they're hidden, it's worth trying the method first (then discontinuing it if it you turn out to be one of th

If, say, 95% of people tend to eat less sweets when they're hidden, it's worth trying the method first (then discontinuing it if it you turn out to be one of the 5%). Is a drug that cures most, but not all, instances of a specific infection useless?