Characteristics of variable – actuarial estimation method
The median is a measure of the center of the distribution. The median is a resistant statistic because outliers and the tails in a skewed distribution do not significantly affect its value.
Nonparametric estimates do not depend on any particular distribution and therefore are good to use when no distribution adequately fits the data.
The median is 77,260.5.
Additional time from Time T until 50% of running units fail – actuarial estimation method
Use the additional time table to determine how much additional time, from a fixed time, passes before a certain percentage of the currently surviving products will fail. For each "Time T", Minitab estimates the additional time that must pass until one-half of the currently surviving products fail.
For the new muffler data, at 50,000 miles, 0.95424 of the new type of mufflers are still running. After an estimated 28,180.1 more miles, an additional 47.71% ((0.95424 x 0.5) x 100) of the mufflers that are still running at 50,000 miles are expected to fail.
Conditional probability of failure – actuarial estimation method
The conditional probability of failure indicates the probability that a product that has survived until the beginning of a particular interval will fail within the interval.
For the new muffler data, a muffler that survived until 50,000 miles has a probability of 0.107892 (or a 10.7892% chance) of failing in the interval of 50,000 to 60,000 miles.
The survival probabilities indicate the probability that the product survives until a particular time. Use these values to determine whether your product meets reliability requirements or to compare the reliability of two or more designs of a product.
For the new muffler data, 0.95424 (or 95.424%) of the new type of mufflers survive at least 50,000 miles.