Question: how to calculate the empirical rule?
Answer: Mean: μ = 100.
Standard deviation: σ = 15.
Empirical rule formula: μ - σ = 100 – 15 = 80. μ + σ = 100 + 15 = 115. 68% of people have an IQ between 80 and 115. μ – 2σ = 100 – 2*15 = 70. μ + 2σ = 100 + 2*15 = 130. 95% of people have an IQ between 70 and 130. μ - 3σ = 100 – 3*15 = 55.