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A dditive Method
         he  ord  additive  denotes the addition of the distinct elements

            y ( t)  =  L ev el +  T r end  +  Seasonality  +  Noise
        An additive trend sho s a linear trend. It is a straight line.

        Multiplicative Method
         he  ord  multiplicative  denotes the multiplication of the distinct elements

            y ( t)  =  L ev el x  T r end  x  Seasonality  x  Noise
        A multiplicative model, like a quadratic or e ponential one, is nonlinear. Over time, changes can increase or decrease. It
        is represented by curved lines.
         et us understand using an e ample.  e use the airlines passenger dataset.  he total number of airline passengers over
        time is seen in this dataset.  he number of passengers on an airline is counted in units of thousands.  rom      to     ,
        there are     monthly observations.
        Do nload the dataset from
        https   ra .githubusercontent.com  bro nlee Datasets master airline passengers.csv
         et us first plot the graph of all the observations using  ython.

        f r om p and as imp or t r ead _ csv
        f r om matp lotlib  imp or t p y p lot

        ser ies =  r ead _ csv ( ' http s: //r aw .githu b u ser content.com/j b r ow nlee/D atasets/master /air line-
        p assenger s.csv ' ,  head er = 0 ,  ind ex _ col= 0 )

        ser ies.p lot( )
        p y p lot.show ( )

                                  assengers























                                                             onth
         et us no  apply the multiplicative model to the above series.






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