Variance and standard deviation definition and calculation
Variance and standard deviation are widely used measures of dispersion of data or, in finance and investing, measures of volatility of asset prices.
Variance is defined and calculated as the average squared deviation from the mean. Standard deviation is calculated as the square root of variance or in full definition, [...]
This article is a step-by-step guide to calculating variance and standard deviation.
Definition of variance
Variance is a measure of dispersion in a set of data. It measures how big the differences are between individual numbers in a set of numbers.
Mathematically it is the average squared difference between each occurrence (each number) and the mean of the [...]
Terminology of option positions may be confusing
Sometimes people have a long put position (they own puts) and they say they are short. They mean their exposure to the underlying stock’s price movement is similar to a short position in the stock (they expect to make a profit when the stock falls).
But in fact the security [...]
