IEC 60605-4 : 2.0

Table of Contents

FOREWORD<br>1 Scope<br>2 Normative references<br>3 Definitions and Symbols<br>&nbsp;&nbsp;&nbsp;3.1 Definitions<br>&nbsp;&nbsp;&nbsp;3.2 Symbols<br>4 Assumptions and requirements<br>&nbsp;&nbsp;&nbsp;4.1 Assumptions and information required for point <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;estimates and confidence intervals<br>&nbsp;&nbsp;&nbsp;4.2 Assumptions and requirements for prediction <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;intervals<br>&nbsp;&nbsp;&nbsp;4.3 Assumptions and requirements for tolerance <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;intervals<br>5 Procedure for calculating point estimates and <br>&nbsp;&nbsp;&nbsp;confidence intervals<br>&nbsp;&nbsp;&nbsp;5.1 Time terminated tests<br>&nbsp;&nbsp;&nbsp;5.2 Analytical procedure - Failure terminated tests<br>6 Prediction intervals for the number of failures in a <br>&nbsp;&nbsp;&nbsp;future period<br>&nbsp;&nbsp;&nbsp;6.1 Two-sided prediction intervals r[L2] and r[U2]<br>&nbsp;&nbsp;&nbsp;6.2 One-sided prediction interval<br>7 Procedure for assigning tolerance intervals<br>&nbsp;&nbsp;&nbsp;7.1 Upper Poisson tolerance bound<br>&nbsp;&nbsp;&nbsp;7.2 Lower Poisson tolerance bound<br>Annex A (informative) Examples <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;A.1 Point estimate of MTTF<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;A.2 Application of lower one-sided 90 % confidence <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;limit on mean time to failure (MTTF)<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;A.3 Application of two-sided 90 % confidence limits <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;on MTTF<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;A.4 Application of a two-sided 90 % prediction <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;interval<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;A.5 Application of upper 90 % tolerance bound at <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;95 % confidence<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;A.6 Application of lower 90 % tolerance bound at <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;95 % confidence<br>Annex B (informative) Relation between confidence, <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;prediction and tolerance intervals<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;B.1 Confidence intervals<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;B.2 Prediction intervals<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;B.3 Tolerance intervals<br>Annex C (normative) Computation of accumulated test <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;time T*<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;C.1 Case 1, one repaired item with constant failure <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;intensity <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;C.2 Case 2, more than one repaired item with <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;identical constant failure intensities<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;C.3 Case 3, non-repaired items<br>Annex D (normative) Tables of fractiles of the <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;chi-squared distribution: X[2][alpha] (nu)<br>Annex E (normative) Integral of the chi-squared <br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;distribution and cumulative Poisson distribution <br>Annex F (normative) 0,95 fractiles of the F distribution<br>Bibliography

Abstract

Gives statistical methods for evaluating point estimates, confidence intervals, prediction intervals and tolerance intervals for the failure rate of items whose time to failure follows an exponential distribution.

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Published
Document Type	Standard
Status	Current
Publisher	International Electrotechnical Committee
Pages
ISBN
Committee	TC 56