The survival plot depicts the probability that the item will survive until a particular time. Thus it is a plot of the reliability of the product over time. The Y-axis displays the probability of survival and the X-axis displays the reliability measurement (time, number of copies, miles driven).

When you do not choose a distribution (when you choose to conduct a nonparametric analysis), the survival plot is a step function with steps at the exact failure times. The function is calculated using the Kaplan-Meier technique.

For the iron cord data, the probability of the new iron cord surviving until 73.7 hours is 0.5. In other words, there is a 50% chance that the iron cord will survive until 73.7 hours.