by Dina H. Abdel Hady, Rania and M. Shalaby
Original Research
New parameters can be introduced to expand families of distributions for added flexibility or to construct covariate models and this could be done in various ways. In this article, we generalize the Laplace distribution using the quadratic rank transmutation map studied by Shaw et al. (2007) to develop a transmuted Laplace distribution (TLD). We provide a comprehensive description of the mathematical properties of the subject distribution along with its reliability behavior. To show that the TLD distribution can be a better model than one based on the LD distribution we use a real data set of number of million revolutions before failure for each of the 23 ball bearings in the life tests and The usefulness of the transmuted Laplace distribution for modeling reliability data is illustrated.
American Journal of Applied Mathematics and Statistics. 2016, 4(3), 94-98. DOI: 10.12691/ajams-4-3-5
Pub. Date: July 11, 2016
11237 Views3082 Downloads
by Waleed M. Alhamdan and Luwai Wazzan
Review Article
A new application of the remarkable (DαG)/G-expansion method based on a fractional order ordinary differential equation is used to find exact solutions of the space-time fractionalsymmetric regularized long wave (SRLW) equation and the space-time fractional Sharma-Tasso-Olver (STO) equation. This method involves Jumarie’s modified Riemann-Liouville derivative and uses some of its basic properties. Exact solutions for both equations are obtained.cialis coupons free
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American Journal of Applied Mathematics and Statistics. 2016, 4(3), 87-93. DOI: 10.12691/ajams-4-3-4
Pub. Date: July 04, 2016
13006 Views3915 Downloads2 Likes
by Mahmoud Riad Mahmoud, Naglaa A. Morad and Moshera A. M. Ahmad
Original Research
For the log-beta log-logistic regression model, we derive the appropriate matrices for assessing the local influence on the parameter estimates under perturbation scheme. Using a set of real data, global and local influences of individual observations on the stated model are considered. Besides, for different parameter settings, sample sizes, and censoring percentages, various simulation studies are performed to the performance of the log-beta log-logistic regression model. In addition, the empirical distribution of the martingale residuals is displayed against the normal distribution for comparison. These studies suggest that the martingale residual has shaped normal form.
American Journal of Applied Mathematics and Statistics. 2016, 4(3), 74-86. DOI: 10.12691/ajams-4-3-3
Pub. Date: July 02, 2016
16856 Views3816 Downloads
by I.A. Iwok
Original Research
This work proposed a method for the estimation of missing values in a stable bivariate autoregressive time series process. Missing observations were created at different positions in a stable bivariate series and the method was applied. Despite its ease of implementation, the obtained results suggested good performance of the method. The estimates obtained were compared with those of other existing methods. The result showed that the proposed method provides better estimates than the existing methods.
American Journal of Applied Mathematics and Statistics. 2016, 4(3), 67-73. DOI: 10.12691/ajams-4-3-2
Pub. Date: June 15, 2016
11182 Views2629 Downloads
by Abdallah S. A. Yaseen, Ahmed M. Gad and Abeer S. Ahmed
Original Research
In longitudinal studies data are collected for the same set of units for two or more occasions. This is in contrast to cross-sectional studies where a single outcome is measured for each individual. Some intended measurements might not be available for some units resulting in a missing data setting. When the probability of missing depends on the missing values, missing mechanism is termed nonrandom. One common type of the missing patterns is the dropout where the missing values never followed by an observed value. In nonrandom dropout, missing data mechanism must be included in the analysis to get unbiased estimates. The parametric fractional imputation method is proposed to handle the missingness problem in longitudinal studies and to get unbiased estimates in the presence of nonrandom dropout mechanism. Also, in this setting the jackknife replication method is used to find the standard errors for the fractionally imputed estimates. Finally, the proposed method is applied to a real data (mastitis data) in addition to a simulation study.coupons for drugs
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American Journal of Applied Mathematics and Statistics. 2016, 4(3), 59-66. DOI: 10.12691/ajams-4-3-1
Pub. Date: May 30, 2016
17235 Views3677 Downloads3 Likes