STATISTICS Types of Data Data can be presented in many ways. The following four data descriptions are in order of least to most in-depth. [Tip: remember with the acronym “NOIR”] -
Normal; Ordinal; Interval; Ratio;
discrete data placed in no particular order. the data is placed in order. ordinal data which is also grouped into equally sized groups. interval data which also has a natural zero point.
Means Below are four common ways of taking a mean average… - Arithmetic: (single period returns in future period) - Geometric: (future compound returns over multiple periods) - Weighted: - Harmonic: Variances Three common variance formulae… - Mean Arithmetic Deviation: - Variance: - Sample Variance: Other Key Formulae Some other key statistical formulae we’ll need to know… - Chebyshev’s Inequality: - Coefficient of Variation: (sigma, σ, is equal to the standard deviation) - Sharpe Ratio: (higher value => lower risk => better investment)