DEFINITION of 'Time Series'
A sequence of numerical data points in successive order, usually occurring in uniform intervals. In plain English, a time series is simply a sequence of numbers collected at regular intervals over a period of time.
INVESTOPEDIA EXPLAINS 'Time Series'
Time series analysis can be useful to see how a given asset, security or economic variable changes over time or how it changes compared to other variables over the same time period. For example, suppose you wanted to analyze a time series of daily closing stock prices for a given stock over a period of one year. You would obtain a list of all the closing prices for the stock over each day for the past year and list them in chronological order. This would be a oneyear, daily closing price time series for the stock.
Delving a bit deeper, you might be interested to know if a given stock's time series shows any seasonality, meaning it goes through peaks and valleys at regular times each year. Or you might want to know how a stock's share price changes as an economic variable, such as the unemployment rate, changes.

Indicator
Indicators are statistics used to measure current conditions ... 
Trend
The general direction of a market or of the price of an asset. ... 
Heteroskedastic
A measure in statistics that refers to the variance of errors ... 
Correlation
In the world of finance, a statistical measure of how two securities ... 
Covariance
A measure of the degree to which returns on two risky assets ... 
Homoskedastic
A statistics term indicating that the variance of the errors ...

How do I calculate correlation between market indicators and specific stocks?
Calculate the correlation coefficient to find the correlation between any two variables, whether they are market indicators, ... Read Full Answer >> 
How far back in a stock's history should you go when gauging its volatility?
While it's always important to assess the overall risk within your own investing strategy, how much historical emphasis you ... Read Full Answer >>

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