Читать книгу Medical Statistics - David Machin - Страница 113

The F‐distribution (Figure 4.14c) is the distribution of the ratio of two chi‐squared distributions and is used in hypothesis testing when we want to compare variances, such as in one‐way analysis of variance (see Section 7.3). It is always positive, but the exact shape depends on the degrees of freedom for the two chi‐squared distributions that determine it.