As is known that the consumer price index (CPI) is one of the most important price indices because of its direct effect on the welfare of the individual and his living.
We have been address the problem of Strongly seasonal commodities in calculating (CPI) and identifying some of the solution.
We have used an actual data for a set of commodities (including strongly seasonal commodities) to calculate the index price by using (Annual Basket With Carry Forward Prices method) . Although this method can be successfully used in the context of seasonal commodities the index does not get rid of the tremendous season fluctuations .
In order to use (CPI) in measuring the general inflation and monthly or quarterly comparison ,we must first decompose the seasonal component and eliminate its effect on the (CPI) series to get a seasonal adjusted series of (CPI) .
Many statistical methods are used to analysis (CPI) series, and one of these methods is the method of time series that takes into account the seasonal variations in the study of phenomena.
test to Ljung-Box We have used Box-Jenkens method in models building and then test the modesl ,also we have found the seasonal adjusted series by using time series method
