The empirical rule describes how points are clustered in a normally-distributed data set. It states that 95% of data fall ...

Using Microsoft Excel you can create charts based on the data and formulas entered in a worksheet. Enter a sample range of numbers in Excel as if you were at an event asking people their ages, for ...

Process inspection schemes using control charts with warning lines are considered and the properties for some schemes based on the observations from the last few samples are evaluated. Tables of ...

Many types of control charts have an ability to detect process changes that can weaken over time depending on the past data observed. This is often referred to as the "inertia problem." We propose a ...

Marshall Hargrave is a stock analyst and writer with 10+ years of experience covering stocks and markets, as well as analyzing and valuing companies. Dr. JeFreda R. Brown is a financial consultant, ...

In response to my article, Is the Stock Market Too Concentrated?, which relied upon standard-deviation calculations to assess investment risk, a reader wrote: “My problem [with your argument] is ...

Use Excel to calculate daily returns and standard deviation to gauge stock volatility. Annualize volatility by multiplying daily standard deviation by the square root of 252. Remember, standard ...