Several employees have submitted different methods of assembling a subassembly. Sample data for each method are: Minutes Required for Assembly Sample Number Lind's Method Szabo's Method Carl's Method Manley's Method 1 16.6 22.4 31.4 18.4 2 17.0 21.5 33.4 19.6 3 16.9 22.6 30.1 17.6 How many treatments are there?