selviytymäkäyriä

Selviytymäkäyrä, often translated as survival curve, is a concept used in various fields, notably medicine, biology, and engineering, to illustrate the proportion of individuals or items that are still functioning or alive over a specific period. It visually represents the probability of survival as a function of time.

In medicine, survival curves are commonly used in clinical trials to show the survival rates of patients with different treatments or conditions. The most famous example is the Kaplan-Meier survival curve, which estimates the survival function from lifetime data. The curve typically starts at 100% survival at time zero and decreases over time, indicating the proportion of individuals who have not yet died or experienced the event of interest.

In reliability engineering, survival curves, often called reliability curves, depict the probability that a component or system will function without failure over time. This helps in predicting product lifespan and planning maintenance schedules. The shape of the curve can reveal different failure patterns, such as early failures, wear-out failures, or constant failure rates.

The axes of a survival curve are time on the horizontal axis and the proportion surviving (or probability of survival) on the vertical axis, ranging from 0 to 1. Analyzing the slope and shape of the curve provides insights into the rate of decline or failure and allows for comparisons between different groups or scenarios.