Statistics — Formula Sheet

x̄ = Σfi xi / Σfi

Class mark = (Upper class limit + Lower class limit) / 2

di = xi - a

x̄ = a + Σfi di / Σfi

ui = (xi - a) / h

Mode = l + ((f1 - f0) / (2f1 - f0 - f2)) × h

If n is odd, median = ((n + 1) / 2)th observation

If n is even, median = average of the (n/2)th and ((n/2) + 1)th observations

Median = l + (((n/2) - cf) / f) × h

Deviations are calculated using d_i = x_i - a, and the mean is found by x̄ = a + Σf_i d_i / Σf_i.

This method uses u_i = (x_i - a)/h, where h is the class size.