Tiheyskäyrät

Tiheyskäyrät, or density curves, are a fundamental concept in statistics used to represent the distribution of a continuous variable. A density curve is a graph where the total area under the curve is equal to 1. This area represents probability. The height of the curve at any given point does not represent probability itself, but rather the relative likelihood of observing values near that point. A higher point on the curve indicates a greater density of data in that region.

Density curves are always on or above the horizontal axis, meaning their values are non-negative. They can take various shapes, such as symmetric, skewed left, or skewed right, mirroring the shape of the underlying data distribution. Common examples of density curves include the normal distribution, which is bell-shaped and symmetric, and the uniform distribution, which is a flat horizontal line indicating that all values in a given range are equally likely.

The area under a density curve between two specified values represents the probability that the variable falls within that range. For instance, the area under the curve between a and b gives P(a ≤ X ≤ b), where X is the random variable. Calculating these areas often involves integration in calculus, but for well-known distributions like the normal distribution, standard tables or statistical software can be used to find probabilities. Density curves are a powerful tool for visualizing and understanding the behavior of statistical data.