Industrial engineers usually know about the bathtub curve, especially in reference to an operating or failing unit. In other words, if enough units from a given population are observed operating and failing over time, it is relatively easy to compute week-by-week (or month-by-month or year-by-year) estimates of the failure rate. The results of the calculated population failure rates over time produces a graph. Because the shape of this failure rate curve resembles the end-to-end section of an antique bathtub, it is widely known as the “bathtub curve.” This type of analysis is usually used in industrial settings. For example, it can describe the expected failure rate of certain electronics over time: initially high; then dropping to 0 failures for most of the system’s lifetime; then rising again to the other end of the “tub” as the electronics “tire out.”