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Table 36 Performance of tolerance intervals based on lognormal distribution when the true distribution is Weibull (G: Lognormal; 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

\(\hat {\alpha }\)

0.0195

0.0215

0.0134

0.0063

0.0344

0.0545

0.0565

0.0503

 

\(\hat {\rho }\)

0.9826

0.9678

0.9592

0.9520

0.9902

0.9810

0.9754

0.9707

 

\(\hat {s}\)

0.0269

0.0248

0.0207

0.0168

0.0183

0.0168

0.0140

0.0113

α= 0.05

\(\hat {\alpha }\)

0.0700

0.0633

0.0455

0.0229

0.1066

0.1316

0.1246

0.1128

 

\(\hat {\rho }\)

0.9657

0.9547

0.9490

0.9441

0.9792

0.9723

0.9688

0.9658

 

\(\hat {s}\)

0.0427

0.0322

0.0248

0.0191

0.0304

0.0221

0.0167

0.0127

α= 0.1

\(\hat {\alpha }\)

0.1200

0.1056

0.0766

0.0422

0.1743

0.1945

0.1781

0.1594

 

\(\hat {\rho }\)

0.9536

0.9464

0.9428

0.9395

0.9710

0.9669

0.9649

0.9630

 

\(\hat {s}\)

0.0525

0.0366

0.0272

0.0204

0.0381

0.0253

0.0183

0.0135

α= 0.2

\(\hat {\alpha }\)

0.2089

0.1773

0.1310

0.0753

0.2744

0.2818

0.2587

0.2329

 

\(\hat {\rho }\)

0.9353

0.9347

0.9344

0.9334

0.9587

0.9595

0.9598

0.9594

 

\(\hat {s}\)

0.0654

0.0424

0.0303

0.0220

0.0484

0.0295

0.0204

0.0146

  

ρ= 0.99

   

ρ= 0.995

   

α = 0.01

\(\hat {\alpha }\)

0.0842

0.2270

0.3715

0.5708

0.1152

0.3247

0.5461

0.7836

 

\(\hat {\rho }\)

0.9965

0.9929

0.9904

0.9881

0.9976

0.9950

0.9932

0.9915

 

\(\hat {s}\)

0.0094

0.0081

0.0069

0.0057

0.0075

0.0062

0.0052

0.0044

α= 0.05

\(\hat {\alpha }\)

0.2350

0.4073

0.5601

0.7285

0.2983

0.5262

0.7235

0.8901

 

\(\hat {\rho }\)

0.9914

0.9886

0.9870

0.9855

0.9937

0.9917

0.9906

0.9895

 

\(\hat {s}\)

0.0167

0.0115

0.0086

0.0066

0.0136

0.0090

0.0068

0.0052

α= 0.1

\(\hat {\alpha }\)

0.3410

0.5074

0.6525

0.7959

0.4173

0.6331

0.7938

0.9264

 

\(\hat {\rho }\)

0.9873

0.9858

0.9849

0.9840

0.9905

0.9895

0.9890

0.9883

 

\(\hat {s}\)

0.0217

0.0135

0.0097

0.0071

0.0179

0.0108

0.0076

0.0056

α= 0.2

\(\hat {\alpha }\)

0.4770

0.6272

0.7471

0.8629

0.5547

0.7397

0.8622

0.9588

 

\(\hat {\rho }\)

0.9809

0.9819

0.9823

0.9821

0.9854

0.9864

0.9868

0.9868

 

\(\hat {s}\)

0.0287

0.0162

0.0109

0.0078

0.0239

0.0131

0.0087

0.0062

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