# MATLAB: How to treat the last observation? Forecasting?

cell matrixforecasting

Dear all,
I have the following cell matrix
A={
`` '24/09/2000'                  [4.1583]    '22/10/2000'              [3.9389]   '19/11/2000'               [4.3944]    '17/12/2000'              [3.9313]   '14/01/2001'               [3.9313]    '11/02/2001'               [3.9313]    '11/03/2001'              [4.0339]}``
I can easily convert the above data points to monthly averages; through the calculation of the weighted average between successive observations.
For instance for the first observation I have
``24*4.1583+ 6*3.9389``
where 24 is the 24 days from month Octomber and 6=(last date of the month-24=30-24) The only problem is how to treat the last observation:
``11*4.0339+?``
One way is to extrapolate but I do not consider this method reliable. The above values are prices. So could I apply some other way? Maybe forecasting taking into account seasonality?
Any help/code provided will greatly appreciated
thanks

• ``A ={'24/09/2000'    4.1583    '22/10/2000'    3.9389    '19/11/2000'    4.3944    '17/12/2000'    3.9313    '14/01/2001'    3.9313    '11/02/2001'    3.9313    '11/03/2001'    4.0339};``
``A = [datenum(A(:,1),'dd/mm/yyyy') cat(1,A{:,2})];A =                    730753                    4.1583                    730781                    3.9389                    730809                    4.3944                    730837                    3.9313                    730865                    3.9313                    730893                    3.9313                    730921                    4.0339``
``xi = datenum(2000,10:16,1)-1;``
``B  = interp1(A(:,1),A(:,2), xi,'linear','extrap');``
``plot(A(:,1),A(:,2),'-dr',xi,B,'-ob')set(gca,'Xtick',sort([A(:,1); xi']),'xgrid','on')datetick('x','dd/mm','keepticks')``