Simple moving averages

Next: Weighted moving averages Up: Calculating moving averages Previous: Calculating moving averages

The n day simple moving average for day d is computed by:

$A_d = \frac{\sum_{i=1}^{n} M_{(d-i)+1}}{n}, n\leq d$

If we have ten measurements, M₁ through M₁₀, and we wish to compute a four day moving average, the moving averages for successive days are:

$A_4 = (M_4+M_3+M_2+M_1)/4, A_5 = (M_5+M_4+M_3+M_2)/4, ... A_{10} = (M_{10}+M_9+M_8+M_7)/4$

We can't compute a four day moving average until we have four days worth of data. That's why the first moving average in this example is A₄.