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الطرائق التقليدية والطرائق البديلة لاختبار جذر الوحدة لاستقرارية السلسلة الزمنية : دراسة مقارنة == Traditional Methods And Alternative Methods To Test The Unit Root For The Stationary of Time Series - A Comparative Study
Author name:
كوثر خضر ناصر الزيدي
Supervisor name:
نزيه عباس المشهداني
General topic:
Administration and Economics
Specific topic:
Statistics
Degree:
Doctorate
University:
Mustansiriyah University
Language:
Arabic
University location:
Baghdad
First pages:
07T4279 - p.pdf
Abstract:
يعد تحليل السلاسل الزمنية من الاساليب العلمية والاحصائية لتمثيل العلاقة لبيانات السلسلة الزمنية وتفسير سلوك الظاهرة من خلال دراسة تطورها التاريخي عبر مراحل زمنية، ويلاحظ في الحياة العملية والتطبيقية ان هناك العديد من السلاسل الزمنية لا تملك صفة الاستقرا | The time - series analysis of scientific methods and statistical representation of the relationship of the time series data and interpret the behavior of the phenomenon through the study of its historical development through the stages of time , and notes in the life process and applied that there are many time series do not have the recipe stability, So researchers began detects this problem and adopted for this purpose several methods of which are the subject of the unit root test , as this test of tests shows the task being equal to the number of roots per the correct number that corresponds to the necessary differences of the time series in order to turn out to be stability,. The condition of stability, of a specimen autoregressive is that all the roots of the equation distinctive located outside the unit circle , and the style of taking the differences necessary in order to transform the time series to the stability, style is not accurate to some extent to the fact that the probability of taking a number of differences more than required leads to inaccuracy of the work , so the test roots style is to know the number of differences required for the series studied the application of statistical methods for this test , and there are several ways to conduct this test , including traditional methods and modalities amended, has been comparisons between the methods used and the proposed method by the researcher through simulation through programs written by the researcher and the adoption of the application (Mat lab) where the comparison was between four models of testing unit root and through the results was reached similarities between the test (ADF, PP) and test(KPSS,LM) So was the adoption of a test (ADF, KPSS) and comparison with the proposed method, where the application has proved that there is a disparity between the test (ADF) and (KPSS) depending on the features and sizes of the samples, and that the proposed method was closer to a (KPSS) test , and have also been using data oil prices immediate (Spot Oil Price) for a time series of the month of January 1988 and up to the month of July 2013 and the application of unit root tests them through the use of application - ready (Eviwes).
