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Table 35 Performance of tolerance intervals based on gamma distribution when the true distribution is Weibull (G: Gamma; F: Weibull)

From: Tolerance intervals in statistical software and robustness under model misspecification

  

n = 10

n = 25

n = 50

n = 100

n = 10

n = 25

n = 50

n = 100

  

ρ= 0.9

   

ρ= 0.95

   

α = 0.01

\(\hat {\alpha }\)

0.0184

0.0190

0.0134

0.0084

0.0243

0.0314

0.0274

0.0219

 

\(\hat {\rho }\)

0.9862

0.9717

0.9609

0.9507

0.9934

0.9862

0.9807

0.9753

 

\(\hat {s}\)

0.0267

0.0243

0.0207

0.0170

0.0171

0.0146

0.0124

0.0103

α= 0.05

\(\hat {\alpha }\)

0.0728

0.0662

0.0530

0.0354

0.0870

0.0930

0.0877

0.0701

 

\(\hat {\rho }\)

0.9671

0.9553

0.9471

0.9397

0.9826

0.9770

0.9731

0.9693

 

\(\hat {s}\)

0.0454

0.0332

0.0255

0.0195

0.0308

0.0210

0.0158

0.0121

α= 0.1

\(\hat {\alpha }\)

0.1338

0.1209

0.0986

0.0677

0.1574

0.1588

0.1411

0.1164

 

\(\hat {\rho }\)

0.9519

0.9442

0.9386

0.9332

0.9734

0.9707

0.9683

0.9657

 

\(\hat {s}\)

0.0571

0.0382

0.0281

0.0208

0.0399

0.0249

0.0178

0.0132

α= 0.2

\(\hat {\alpha }\)

0.2529

0.2176

0.1778

0.1332

0.2769

0.2610

0.2310

0.2028

 

\(\hat {\rho }\)

0.9283

0.9287

0.9272

0.9249

0.9585

0.9615

0.9617

0.9609

 

\(\hat {s}\)

0.0717

0.0444

0.0313

0.0224

0.0523

0.0300

0.0204

0.0145

  

ρ= 0.99

   

ρ= 0.995

   

α = 0.01

\(\hat {\alpha }\)

0.0410

0.0800

0.1212

0.1808

0.0462

0.1072

0.1755

0.3005

 

\(\hat {\rho }\)

0.9983

0.9965

0.9949

0.9931

0.9989

0.9980

0.9970

0.9958

 

\(\hat {s}\)

0.0081

0.0055

0.0047

0.0040

0.0064

0.0038

0.0032

0.0027

α= 0.05

\(\hat {\alpha }\)

0.1381

0.2099

0.2633

0.3537

0.1588

0.2609

0.3565

0.5027

 

\(\hat {\rho }\)

0.9944

0.9932

0.9921

0.9908

0.9963

0.9957

0.9951

0.9942

 

\(\hat {s}\)

0.0155

0.0089

0.0064

0.0049

0.0122

0.0064

0.0045

0.0035

α= 0.1

\(\hat {\alpha }\)

0.2319

0.3033

0.3665

0.4577

0.2608

0.3714

0.4733

0.6154

 

\(\hat {\rho }\)

0.9908

0.9908

0.9903

0.9895

0.9937

0.9940

0.9938

0.9933

 

\(\hat {s}\)

0.0209

0.0110

0.0075

0.0054

0.0167

0.0081

0.0054

0.0039

α= 0.2

\(\hat {\alpha }\)

0.3680

0.4369

0.5039

0.5919

0.4112

0.5082

0.6106

0.7335

 

\(\hat {\rho }\)

0.9844

0.9872

0.9878

0.9877

0.9889

0.9914

0.9920

0.9919

 

\(\hat {s}\)

0.0288

0.0139

0.0088

0.0061

0.0234

0.0105

0.0065

0.0045

  1. The bolded values are \({\hat \alpha }\) within \(\pm 2 \sqrt {\alpha (1-\alpha)/M}\) and \({\hat \rho }\) within \(\pm 2 \sqrt {\rho (1-\rho)/M}\)