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2. In terms of the 20,000 hour extrapolation temperature estimations the motorette tests exhibited approximately a 3 to 1 increase in the average per cent of error over the twist tests. 3. In terms of the partial-data estimations faIling within the complete-data 95% confidence limits the median method rated first with a perfect score of 100% and the other two methods second with a score of 90% each. 4. When comparing the width of the complete-data confidence limits of the motorette and twist tests, the motorette confidence limits were, on the average, 32.1% wider. 5. The average over-all time saved was 16.5% (7.4 weeks) for the median method and 21.7% (10.4 weeks) for either of the other two methods. 6. When considered separately, the average per cent of time saved using the median method is 12 .5% for twists and 20.4% for motorettes. For the other two methods it is 17.5% for twists and 26.1 % (30% if considering humidification time) for motorettes. Conclusions and RecommendationsOn the basis of this study the following conclusions and recommendations are presented:1. The estimation of thermal-life values for electrical insulation using truncated data has been proven valid, and a substantial savings of aging time can be realized by its use, particularly when applied to motorette tests. 2. The median method offers the greatest degree of accuracy and reliability as compared to the other two methods studied.

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