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Time series is a series of data points in which each data point is associated with a timestamp.

Time series analysis comprises methods for analyzing time-series data in order to extract meaningful statistics and other characteristics of the data. Time series forecasting is the use of a model to predict future values based on previously observed values.
Example – Rainfall in an area for a complete year, price of a stock in the stock market at different points of time in the day.
A decision tree is a graph to represent choices and their results in the form of a tree. The nodes in the graph represent an event or choice and the edges of the graph represent the decision rules or conditions. It is mostly used in Machine Learning and Data Mining applications using R.
In the random forest approach, a large number of decision trees are created. Every observation is fed into every decision tree. The most common outcome for each observation is used as the final output. A new observation is fed into all the trees and taking a majority vote for each classification model.

An error estimate is made for the cases which were not used while building the tree. That is called an OOB (Out-of-bag) error estimate which is mentioned as a percentage.
A flowchart is a type of diagram which represents an algorithm or flow or process showing the steps as boxes of various kinds, and their order by connecting them with arrows. Flowcharts are used in designing and documenting simple processes or programs. The two most common types of boxes in a flowchart are:

-a processing step, usually called activity and denoted as a rectangular box

-a decision usually denoted as a diamond.
The purpose of a flow chart is to provide people with a common language or reference point when dealing with a project or process. It gives a pictorial representation of a problem in a structured way(flow).