The cumulative failure plot depicts the probability that the item will fail after a particular time. Therefore, the plot shows the failure probability of the product over time. The Y-axis displays the probability of failure and the X-axis displays the reliability measurement (time, number of copies, miles driven).
For a nonparametric analysis, the cumulative failure plot is a step function with steps at the end points of each interval. In this example, the function is calculated using the actuarial estimation method.
For the new muffler data, the probability that the new type of mufflers will fail by 50,000 miles is 0.05. In other words, the mufflers have a 5% chance of failing at or before 50,000 miles.