Students should understand that a randomized experiment can be used to compare two treatments. A good way to compare the two treatments statistically is through at-test. (If your students are confused, just do Mr. T impressions: "I pity the fool who doesn't use a t-test for these types of problems!")
The t-test spits out a number that, when used along with a table further provided below, can help us determine the significant difference between two treatment options. The most commonly used α value is 0.05, but you can change that at will in your classroom.