Variance

Definition of 'Variance'


A measurement of the spread between numbers in a data set. The variance measures how far each number in the set is from the mean. Variance is calculated by taking the differences between each number in the set and the mean, squaring the differences (to make them positive) and dividing the sum of the squares by the number of values in the set. 



Investopedia explains 'Variance'




Variance is used in statistics for probability distribution. Since variance measures the variability (volatility) from an average or mean, and volatility is a measure of risk, the variance statistic can help determine the risk an investor might take on when purchasing a specific security. 

A variance value of zero indicates that all values within a set of numbers are identical; all variances that are non-zero will be positive numbers. A large variance indicates that numbers in the set are far from the mean and each other, while a small variance indicates the opposite. 

Statisticians use variance to see how individual numbers relate to each other within a data set, rather than using broader mathematical techniques such as arranging numbers into quartiles. A drawback to variance is that it gives added weight to numbers far from the mean (outliers), since squaring these numbers can skew interpretations of the data.

 



comments powered by Disqus
Hot Definitions
  1. Debit Spread

    Two options with different market prices that an investor trades on the same underlying security. The higher priced option is purchased and the lower premium option is sold - both at the same time. The higher the debit spread, the greater the initial cash outflow the investor will incur on the transaction.
  2. Odious Debt

    Money borrowed by one country from another country and then misappropriated by national rulers. A nation's debt becomes odious debt when government leaders use borrowed funds in ways that don't benefit or even oppress citizens. Some legal scholars argue that successor governments should not be held accountable for odious debt incurred by earlier regimes, but there is no consensus on how odious debt should actually be treated.
  3. Takeover

    A corporate action where an acquiring company makes a bid for an acquiree. If the target company is publicly traded, the acquiring company will make an offer for the outstanding shares.
  4. Harvest Strategy

    A strategy in which investment in a particular line of business is reduced or eliminated because the revenue brought in by additional investment would not warrant the expense. A harvest strategy is employed when a line of business is considered to be a cash cow, meaning that the brand is mature and is unlikely to grow if more investment is added.
  5. Stop-Limit Order

    An order placed with a broker that combines the features of stop order with those of a limit order. A stop-limit order will be executed at a specified price (or better) after a given stop price has been reached. Once the stop price is reached, the stop-limit order becomes a limit order to buy (or sell) at the limit price or better.
  6. Pareto Principle

    A principle, named after economist Vilfredo Pareto, that specifies an unequal relationship between inputs and outputs. The principle states that, for many phenomena, 20% of invested input is responsible for 80% of the results obtained. Put another way, 80% of consequences stem from 20% of the causes.
Trading Center