Asymptotic confidence intervals for the Pearson correlation via skewness and kurtosis

2017 ◽  
Vol 71 (1) ◽  
pp. 167-185 ◽  
Author(s):  
Anthony J. Bishara ◽  
Jiexiang Li ◽  
Thomas Nash
Keyword(s):  
Confidence Intervals ◽  
Pearson Correlation ◽  
Asymptotic Confidence Intervals ◽  
Skewness And Kurtosis

Masking Colored Substrates Using Monolithic and Bilayer CAD-CAM Ceramic Structures

2017 ◽  
Vol 42 (4) ◽  
pp. 387-395 ◽  
Author(s):  
GR Basso ◽  
AB Kodama ◽  
AH Pimentel ◽  
MR Kaizer ◽  
A Della Bona ◽  
...  
Keyword(s):  
Confidence Intervals ◽  
Pearson Correlation ◽  
Lithium Disilicate ◽  
Color Difference ◽  
Color Variation ◽  
Color Coordinates ◽  
Cad Cam ◽  
Ceramic Thickness ◽  
Monolithic Structures ◽  
Monolithic Structure

SUMMARY Objective: To evaluate the masking ability and translucency of monolithic and bilayer CAD-CAM ceramic structures. Methods: Discs of high translucency (HT) and low translucency (LT) lithium disilicate–based ceramic (IPS e.max CAD) with different thicknesses (0.7, 1, 1.5, and 2 mm) were evaluated as a monolithic structure or combined (bilayer) with a 0.5-mm-thick zirconia framework (IPS e.max ZirCAD). The masking ability and translucency were calculated based on CIE L*a*b* color coordinates measured with a spectrophotometer (SP60, X-Rite). The translucency parameter (TP) was calculated using color coordinates measured over standard white-and-black backgrounds. The masking ability was calculated by CIEDE2000 color difference metric (ΔE00) for each specimen measured over a tooth-colored substrate (shade A2) compared to three darker backgrounds (shade C4 and two metal substrates). Confidence intervals (CI) for the means (95% CI) were calculated for TP and ΔE00. The Pearson correlation between ΔE00 and TP was investigated for monolithic and bilayer structures over all backgrounds. Results: The thinner the lithium disilicate layer, the greater the translucency and the higher the ΔE00 values. The effect of ceramic thickness on both translucency and masking ability was more pronounced for the monolithic structures. In addition, monolayers always presented a greater color variation than their bilayer counterparts. The metallic background produced greater ΔE00 than the C4-shaded substrate. Conclusion: Monolithic veneers were able to mask C4-shaded background but did not mask metallic backgrounds. Bilayer structures showed greater shade masking ability than monolithic structures.

scholarly journals Reliability Analysis of the New Exponential Inverted Topp–Leone Distribution with Applications

Entropy ◽  
2021 ◽  
Vol 23 (12) ◽  
pp. 1662
Author(s):  
Ahmed Sayed M. Metwally ◽  
Amal S. Hassan ◽  
Ehab M. Almetwally ◽  
B M Golam Kibria ◽  
Hisham M. Almongy
Keyword(s):  
Reliability Analysis ◽  
Confidence Intervals ◽  
Hazard Rate ◽  
Shape Parameter ◽  
Quantile Function ◽  
Proposed Model ◽  
Distribution Parameters ◽  
Rate Functions ◽  
New Distribution ◽  
Skewness And Kurtosis

The inverted Topp–Leone distribution is a new, appealing model for reliability analysis. In this paper, a new distribution, named new exponential inverted Topp–Leone (NEITL) is presented, which adds an extra shape parameter to the inverted Topp–Leone distribution. The graphical representations of its density, survival, and hazard rate functions are provided. The following properties are explored: quantile function, mixture representation, entropies, moments, and stress–strength reliability. We plotted the skewness and kurtosis measures of the proposed model based on the quantiles. Three different estimation procedures are suggested to estimate the distribution parameters, reliability, and hazard rate functions, along with their confidence intervals. Additionally, stress–strength reliability estimators for the NEITL model were obtained. To illustrate the findings of the paper, two real datasets on engineering and medical fields have been analyzed.

scholarly journals Inference on reliability of stress-strength model with Peng-Yan extended Weibull distributions

Filomat ◽  
2021 ◽  
Vol 35 (6) ◽  
pp. 1927-1948
Author(s):  
Milan Jovanovic ◽  
Bojana Milosevic ◽  
Marko Obradovic ◽  
Zoran Vidovic
Keyword(s):  
Asymptotic Distribution ◽  
Confidence Intervals ◽  
Real Data ◽  
Independent Random Variables ◽  
Likelihood Estimator ◽  
Conjugate Priors ◽  
Asymptotic Confidence Intervals ◽  
Exact Confidence Intervals ◽  
Extended Weibull Distribution ◽  
Interval Estimator

In this paper we estimate R = PfX < Yg when X and Y are independent random variables following the Peng-Yan extended Weibull distribution. We find maximum likelihood estimator of R and its asymptotic distribution. This asymptotic distribution is used to construct asymptotic confidence intervals. In the case of equal shape parameters, we derive the exact confidence intervals, too. A procedure for deriving bootstrap-p confidence intervals is presented. The UMVUE of R and the UMVUE of its variance are derived and also the Bayes point and interval estimator of R for conjugate priors are obtained. Finally, we perform a simulation study in order to compare these estimators and provide a real data example.

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