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Table 38 Performance of tolerance intervals based on Weibull distribution when the true distribution is lognormal (G: Weibull; F: Lognormal)

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

\(\hat {\alpha }\)

0.0114

0.0064

0.0021

0.0004

0.0191

0.0149

0.0102

0.0047

 

\(\hat {\rho }\)

0.9915

0.9846

0.9777

0.9705

0.9951

0.9916

0.9877

0.9835

 

\(\hat {s}\)

0.0226

0.0181

0.0158

0.0135

0.0163

0.0120

0.0104

0.0089

α= 0.05

\(\hat {\alpha }\)

0.0433

0.0196

0.0086

0.0019

0.0648

0.0460

0.0308

0.0153

 

\(\hat {\rho }\)

0.9796

0.9743

0.9688

0.9631

0.9874

0.9851

0.9821

0.9789

 

\(\hat {s}\)

0.0376

0.0252

0.0198

0.0157

0.0281

0.0175

0.0134

0.0105

α= 0.1

\(\hat {\alpha }\)

0.0722

0.0360

0.0161

0.0037

0.1062

0.0777

0.0516

0.0276

 

\(\hat {\rho }\)

0.9703

0.9676

0.9634

0.9589

0.9813

0.9809

0.9788

0.9763

 

\(\hat {s}\)

0.0466

0.0292

0.0220

0.0168

0.0354

0.0206

0.0151

0.0114

α= 0.2

\(\hat {\alpha }\)

0.1239

0.0655

0.0304

0.0080

0.1705

0.1273

0.0857

0.0523

 

\(\hat {\rho }\)

0.9566

0.9584

0.9565

0.9536

0.9720

0.9751

0.9744

0.9730

 

\(\hat {s}\)

0.0578

0.0341

0.0246

0.0182

0.0446

0.0244

0.0171

0.0125

  

ρ= 0.99

   

ρ= 0.995

   

α = 0.01

\(\hat {\alpha }\)

0.0450

0.0698

0.0923

0.1367

0.0566

0.1061

0.1650

0.2684

 

\(\hat {\rho }\)

0.9980

0.9971

0.9958

0.9942

0.9985

0.9980

0.9971

0.9960

 

\(\hat {s}\)

0.0096

0.0059

0.0049

0.0042

0.0081

0.0046

0.0037

0.0032

α= 0.05

\(\hat {\alpha }\)

0.1302

0.1664

0.2084

0.2677

0.1566

0.2321

0.3193

0.4482

 

\(\hat {\rho }\)

0.9944

0.9942

0.9933

0.9921

0.9957

0.9959

0.9953

0.9944

 

\(\hat {s}\)

0.0176

0.0093

0.0068

0.0053

0.0151

0.0074

0.0053

0.0041

α= 0.1

\(\hat {\alpha }\)

0.1958

0.2415

0.2863

0.3544

0.2357

0.3185

0.4176

0.5446

 

\(\hat {\rho }\)

0.9912

0.9922

0.9917

0.9908

0.9931

0.9943

0.9941

0.9935

 

\(\hat {s}\)

0.0227

0.0113

0.0079

0.0059

0.0197

0.0092

0.0062

0.0046

α= 0.2

\(\hat {\alpha }\)

0.2993

0.3383

0.3897

0.4597

0.3499

0.4338

0.5293

0.6562

 

\(\hat {\rho }\)

0.9861

0.9893

0.9895

0.9892

0.9890

0.9920

0.9924

0.9922

 

\(\hat {s}\)

0.0294

0.0140

0.0093

0.0066

0.0257

0.0115

0.0074

0.0052

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