Time Series for Actuaries

Abhishek
7 min readOct 8, 2021

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Time Series

What is a Time Series?

A time series is defined as the sequence of events that occur over time. It’s just a series of timely data points. In time series, time is often an independent variable and purpose is often predicting the future. The time series adds a clear order dependence between the sightings: the magnitude of the time. In a typical machine learning database, the database is a collection of equally managed views when predicting the future.
The time series may have one or more variations that change over time.
If there is one variation that varies over time, we call it the Univariate time series. If there is more than one variation it is called the Multivariate time series. For example, a tri-axial accelerometer. There are three variables in each, one for each axis (x, y, z) and vary at the same time over time. Over a period of time, the viewing structure provides an additional source of information to be analyzed and used in the prediction process. A time series is generally assumed to be produced at divided time intervals (eg daily temperatures), hence the so-called standard time series. But time series details do not have to come at regular intervals. In that case, it is called a series of unusual times. In a series of irregular periods, the data are sequentially sequential, but estimates may not occur at regular intervals.

Time Series Analysis

Time series analysis removes plausible statistics and other data features to understand it. Time series analysis can help make better predictions, but this is not really the main purpose of the analysis. The process of analyzing time series contains methods that try to understand the nature of the series and are often useful in predicting the future and imitating it. This field of study seeks the “why” behind the time series database.

Applications

The time series is used in various fields such as mathematical finance, production, event data (e.g. click-through sounds and app events), IoT data, and generally in any field of applied science and engineering that includes temporal measurements.

What are Markov chains?

One asset that makes the study of the random process much easier is the “Markov” property. Informal, Markov’s property states that, through a random process, that if we know the amount taken by the process in a given time, we will not get more information about future behavior by collecting more information about the past. In terms of more statistical terms, at any given time, the conditional distribution of future conditions of the process given to current and past provinces depends only on the current situation and not on other previous provinces (non-memory assets). The random process with Markov’s property is called the Markov process.

Autocovariance

Autocovariance is defined as the covariance between the current value (xt) and the former value (xt-1) and the current value (xt) with (xt-2). It’s also defined as ϒ. Presently it means that it’ll not change if it’s a series of fixed epochs. So the formula will be;

Autocovariance for time series data

Autocovariance (auto means itself) of (xt) and (xt-1) is defined as the covariance between the same variable with different values.

Autocorrelation

Over a period of time we will deal with the duration of wr time as the company’s sales over the years (predicting feature temperature, ozone level, etc.). While predicting a company’s sale of a feature the previous sale will have a greater impact on the sale of the feature than the previous one. Then find the link between current (xt) and previous sales (xt-1) and then (xt) and (xt-2), (xt-3), etc … to find the combination in the same column using the default.
The Autocorrelation (ACF) function of a timeline is defined as,

Autocorrelation

White Noise

If our model of the selected time series is able to “define” the serial integration of the visual, then the residues themselves are not in sequence.
This means that each element of a series of unrelated residual sequences is an independent recognition from a particular distribution of opportunities. That is, the fossils themselves are independent and distributed in the same way (i.i.d.).
So, if we have to start creating time series models that define any serial integration, it seems natural to start with a process that generates random variables from a particular distribution. This leads directly to the concept of white (different) sound:
Think of a time series {wt: t = 1,… n}. If the series objects, wi, are independent and distributed in the same way (iid), with the definition of zero, the variance σ2, and there is no serial interaction (e.g. cor (wi, wj) ≠ 0, ≠ i ≠ j) then we say that the timeline has a distinct white noise (DWN).
In particular, if wi values ​​are deducted from the standard distribution, then the series is known as Gaussian White Noise.
White Noise is helpful in most cases. In particular, it can be used to mimic a “performance” series.
As we have said before, the historical period is the only example of this. If we can simulate a lot of understanding then we can create “multiple histories” and thus generate statistics for other parameters of certain models. This will help us to improve our models and thus increase the accuracy of our predictions.

White Noise Graph

ARIMA Models

ARIMA models, in theory, are the most common category of time-series predictor models that can be “standing” separately (if necessary), perhaps in combination with non-linear modifications such as input or reduction (if necessary). Random variables that are a series of time stops if their mathematical properties remain constant over time. The vertical sequence is unconventional, its variation surrounding its meaning rather than constant consistency, and it rotates in a consistent manner, i.e., random time patterns always look the same in the mathematical sense. The latter situation implies that its automatic deviation (conjunction with its previous deviation of the meaning) remains unchanged over time, or equally, that its power remains constant over time. The random variation of this form can be viewed (as usual) as a combination of signal and sound, and the signal (if one appears) can be a pattern of rapid or minor relapse, or sinusoidal oscillation, or rapid signal exchange, and can be part of a particular season. The ARIMA model can be viewed as a “filter” that attempts to separate the signal from the sound, and then the signal is re-specified in the future to obtain predictions.
ARIMA’s predictive statistic for a series of fixed periods (e.g., type of reversal) is a number in which the forecasts contain inconsistencies and/or residual climatic errors. Leo:
The predicted value of Y = fixed and/or estimated value of one or more Y values ​​and/or estimated value of one or more recent errors.

ARIMA Model for predicting stock price for TESLA

GARCH Models

GARCH models describe financial markets in which volatility can change, becoming more volatile during periods of financial crises or world events and less volatile during periods of relative calm and steady economic growth.

Time Series for GARCH Model

Conclusion

Time series analysis is required for every company to understand the timing, timing, trends, and randomness in sales and other attributes.
‘Time’ is the most important factor in ensuring success in business. It is difficult to keep up with the passage of time. However, technology has improved some of the powerful techniques we use to ‘see things’ ahead of time. Don’t worry, I’m not talking about Time Machine. Let’s be realistic here!

Actuarial Exams

To achieve actuarial status in the United States or Canada, candidates must pass a series of tests conducted by the Society of Actuaries (SOA) and / or the Casualty Actuarial Society (CAS). SOA tests are named after letters and numbered CAS tests. The first three of these tests are called preliminary tests, and each community accepts the tests of the other. Students must also complete an accredited course, known as Validation by Educational Experience (VEE).

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Abhishek
Abhishek

Written by Abhishek

writer with epic wanderlust. finding beauty in the everyday. you’ve got this. nyc

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