Survival and cumulative probabilities
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What is the probability that a submarine hull will survive a given strength of shock? At a given pesticide application, what is the probability that an insect survives? You are looking for survival probabilities - estimates of the proportion of units that survive at a certain stress level.

When you request survival probabilities, they are displayed in a table in the Session window. In this example, we exposed light bulbs to various voltages and recorded whether or not the bulb burned out before 800 hours. Then we requested a survival probability for light bulbs subjected to 117 volts:

Table of Percentiles

The probability of a bulb lasting past 800 hours is 0.7692 at 117 volts.

The cumulative failure probabilities are the likelihood of failing rather than surviving. In this case, the probability of failing before 800 hours at 117 volts is 0.2308.