Derive the quantization formula based upon the variance of a sinewave and the variance of distortion due to quantization.
SDR = 6(A/Δ)2
This is the signal to distortion (SDR) ratio for a quantized sinewave. A is the amplitude of the quantized sinewave and Delta is the quantization interval of the analog to digital converter, and the quantization performed is rounding.
Using the variance of a random variable based upon statistical samples. The ratio of these two variances is the signal to distortion ratio for the quantized sine wave.