Habshah  Midi, Ehab  A. Mahmood, Abdul  Ghapor Hussin, Jayanthi  Arasan, 
    Robust Trimmed Mean Direction to Estimate Circular Location
Parameter in the Presence of Outliers,
    Journal of Engineering and Applied Sciences,
    Volume 13,Issue 16,
    2018,
    Pages 6612-6615,
    ISSN 1816-949x,
    jeasci.2018.6612.6615,
    (https://makhillpublications.co/view-article.php?doi=jeasci.2018.6612.6615)
    Abstract: Mean direction is a good measure to estimate circular location parameter in univariate circular data.
However, it is bias and cause misleading when the circular data has some outliers, especially with increasing
ratio of outliers. Trimmed mean is one of robust method to estimate location parameter. Therefore in this study,
it is focused to find a robust formula for trimming the circular data. This proposed method is compared with
mean direction, median direction and M estimator for clean and contaminated data. Results of simulation study
and real data prove that trimmed mean direction is very successful and the best among them.
    Keywords: Trimmed mean direction;mean direction;median direction;circular distance;M estimator;Malaysia