研究了无穷方差序列均值变点的检测问题.首先基于 CUSUM 函数,通过 Ratio 检验方法,构造无穷方差序列均值变点的比率检验统计量,其次证明了检验统计量在原假设和备择假设下的极限分布,最后数值模拟表明本方法对无穷方差序列均值变点检...研究了无穷方差序列均值变点的检测问题.首先基于 CUSUM 函数,通过 Ratio 检验方法,构造无穷方差序列均值变点的比率检验统计量,其次证明了检验统计量在原假设和备择假设下的极限分布,最后数值模拟表明本方法对无穷方差序列均值变点检测的有效性.展开更多
This article addresses a stochastic ratio-dependent predator-prey system with Leslie-Gower and Holling type II schemes. Firstly, the existence of the global positive solution is shown by the comparison theorem of stoc...This article addresses a stochastic ratio-dependent predator-prey system with Leslie-Gower and Holling type II schemes. Firstly, the existence of the global positive solution is shown by the comparison theorem of stochastic differential equations. Secondly, in the case of persistence, we prove that there exists a ergodic stationary distribution. Finally, numerical simulations for a hypothetical set of parameter values are presented to illustrate the analytical findings.展开更多
This paper is an extension and generalization of the study carried out by [1] on the estimation of the population ratio (R) of the population means of two variables (y and x) under Simple Random Sampling (SRS) scheme,...This paper is an extension and generalization of the study carried out by [1] on the estimation of the population ratio (R) of the population means of two variables (y and x) under Simple Random Sampling (SRS) scheme, using a variable transformation of the auxiliary variable, x. All the six estimators proposed by [1] are easily identified as special cases of the proposed class of estimators. Asymptotic properties of the proposed class of estimators are derived theoretically and subsequently verified using empirical illustrations. Some of the proposed estimators are found to have relatively large gains in efficiency over the customary ratio estimator, ?for the given data set.展开更多
Two posterior distributions for the mean of the Laplace distribution are obtained by deriving the distributions of the product XY and the ratio X/Y when X and Y are Student＇s t and Laplace random variables distribute...Two posterior distributions for the mean of the Laplace distribution are obtained by deriving the distributions of the product XY and the ratio X/Y when X and Y are Student＇s t and Laplace random variables distributed independently of each other. Tabulations of the associated percentage points are given along with computer programs for generating them.展开更多
Background: In the diagnosis of prostatic diseases, the need for markers other than prostate specific antigen (PSA) has been increasing in recent years. So, we aimed to determine the predictive value, the neutrophil l...Background: In the diagnosis of prostatic diseases, the need for markers other than prostate specific antigen (PSA) has been increasing in recent years. So, we aimed to determine the predictive value, the neutrophil lymphocyte ratio, platelet-to-lymphocyte ratio and mean platelet volume before prostate biopsy in predicting the results of pathology. Transrectal ultrasound-guided biopsy of the prostate was performed because of high PSA values and compared values of these parameters to predict of pathology results. Methods: 2715 patients who underwent 10 - 12 quadrant transrectal ultrasound-guided prostate biopsies between January 2008 and January 2018 have been evaluated retrospectively. Patients were divided into groups according to the biopsy pathology results by benign (group 1), atypical small acinar proliferation (ASAP) (group 2) and prostate cancer (group 3). A total of 204 patients who were benign prostate hyperplasia in 71 patients (34.8%), atypical small acinar proliferation in 80 (39.21%) and prostate adenocarcinoma (PCa) in 53 patients (25.98%) were included in the study by systematic sampling. Before the biopsy total PSA (tPSA), free PSA (fPSA), rate of percentage of free to total prostate specific antigen (f/tPSA) rate, PSA density (PSA-D), white blood cell (WBC) count, blood neutrophil count (NC), blood lymphocyte count (LC), neutrophil lymphocyte ratio (NLR), mean platelet volume (MPV), platelet count (PLT) and platelet-to-lymphocyte ratio (PLR) were measured and compared in all groups. Differences in continuous variables were assessed using the ANOVA. Logistic regression was used to analyze the linear relationship between predictive variables and pathology results. P < 0.05 was considered statistically significant. Results: NLR and PLR values were lower in group 1 than group 2 and were found statistically significant between in group 1 and group 2 (p: 0.03 and p: 0.02, respectively). MPV value was found 1.7 times higher in patients who were diagnosed with ASAP pathology than those with benign pathologies. Although there was statistically significant increase in MPV values in logistic regression results, no statistically significant diagnostic value was found. In addition MPV value was found 0.5 times higher in patients who were diagnosed patients with ASAP than prostate cancer group. ROC analysis showed that the optimal threshold was 7.65 femtoliter (sensitivity: 51%;specificity: 30%) and was found to be a statistically significant diagnostic value to distinguish groups 2 and 3. The lowest value of MPV was found in group 3. Conclusions: In cases where the PSA value is insufficient in predicting the pathology result, the effect of NLR, PLR and MPV on differential diagnosis can be kept in mind. While NLR and PLR are more useful in the diagnosis of ASAP, MPV is more effective in the diagnosis of malignancy.展开更多
基金supported by NSFC of China Grant(11371085)the Fundamental Research Funds for the Central Universities(15CX08011A)
文摘This article addresses a stochastic ratio-dependent predator-prey system with Leslie-Gower and Holling type II schemes. Firstly, the existence of the global positive solution is shown by the comparison theorem of stochastic differential equations. Secondly, in the case of persistence, we prove that there exists a ergodic stationary distribution. Finally, numerical simulations for a hypothetical set of parameter values are presented to illustrate the analytical findings.
文摘This paper is an extension and generalization of the study carried out by [1] on the estimation of the population ratio (R) of the population means of two variables (y and x) under Simple Random Sampling (SRS) scheme, using a variable transformation of the auxiliary variable, x. All the six estimators proposed by [1] are easily identified as special cases of the proposed class of estimators. Asymptotic properties of the proposed class of estimators are derived theoretically and subsequently verified using empirical illustrations. Some of the proposed estimators are found to have relatively large gains in efficiency over the customary ratio estimator, ?for the given data set.
文摘Two posterior distributions for the mean of the Laplace distribution are obtained by deriving the distributions of the product XY and the ratio X/Y when X and Y are Student＇s t and Laplace random variables distributed independently of each other. Tabulations of the associated percentage points are given along with computer programs for generating them.
文摘Background: In the diagnosis of prostatic diseases, the need for markers other than prostate specific antigen (PSA) has been increasing in recent years. So, we aimed to determine the predictive value, the neutrophil lymphocyte ratio, platelet-to-lymphocyte ratio and mean platelet volume before prostate biopsy in predicting the results of pathology. Transrectal ultrasound-guided biopsy of the prostate was performed because of high PSA values and compared values of these parameters to predict of pathology results. Methods: 2715 patients who underwent 10 - 12 quadrant transrectal ultrasound-guided prostate biopsies between January 2008 and January 2018 have been evaluated retrospectively. Patients were divided into groups according to the biopsy pathology results by benign (group 1), atypical small acinar proliferation (ASAP) (group 2) and prostate cancer (group 3). A total of 204 patients who were benign prostate hyperplasia in 71 patients (34.8%), atypical small acinar proliferation in 80 (39.21%) and prostate adenocarcinoma (PCa) in 53 patients (25.98%) were included in the study by systematic sampling. Before the biopsy total PSA (tPSA), free PSA (fPSA), rate of percentage of free to total prostate specific antigen (f/tPSA) rate, PSA density (PSA-D), white blood cell (WBC) count, blood neutrophil count (NC), blood lymphocyte count (LC), neutrophil lymphocyte ratio (NLR), mean platelet volume (MPV), platelet count (PLT) and platelet-to-lymphocyte ratio (PLR) were measured and compared in all groups. Differences in continuous variables were assessed using the ANOVA. Logistic regression was used to analyze the linear relationship between predictive variables and pathology results. P < 0.05 was considered statistically significant. Results: NLR and PLR values were lower in group 1 than group 2 and were found statistically significant between in group 1 and group 2 (p: 0.03 and p: 0.02, respectively). MPV value was found 1.7 times higher in patients who were diagnosed with ASAP pathology than those with benign pathologies. Although there was statistically significant increase in MPV values in logistic regression results, no statistically significant diagnostic value was found. In addition MPV value was found 0.5 times higher in patients who were diagnosed patients with ASAP than prostate cancer group. ROC analysis showed that the optimal threshold was 7.65 femtoliter (sensitivity: 51%;specificity: 30%) and was found to be a statistically significant diagnostic value to distinguish groups 2 and 3. The lowest value of MPV was found in group 3. Conclusions: In cases where the PSA value is insufficient in predicting the pathology result, the effect of NLR, PLR and MPV on differential diagnosis can be kept in mind. While NLR and PLR are more useful in the diagnosis of ASAP, MPV is more effective in the diagnosis of malignancy.
