$2 (; - )2 xi n - 1 Suppose we wish to calculate the variance (the formula for variance is shown above). The next few questions will help you break the solution down into steps. The first step is to subtract x_i from x-bar, but to do that, we need to recognize what each x_i is. For example, what is x_1? For the sake of simplicity, suppose you have a small sample 5.02 kg, 5.07 kg, 5.21 kg.