ABSTRACT
Statistical analyses, once a rarity in medical journals, are routinely encountered in the medical literature, and veterinary journals are no exception. Statistical analyses often have immense practical importance since research results are frequently the basis for decisions about patient care. Statistical tests reported in the medical literature are usually used to disprove the null hypothesis that no difference exists between groups. Power is the probability that a study will find a statistically significant difference when one exists. Statistical tests are referred to as either parametric or nonparametric. Many statistical tests for measurement variables assume that data are normally distributed. Probability sampling provides a scientific basis for saying that the intended sample represents the accessible population and for computing confidence intervals and statistical significance. The validity of a statistical test depends on certain assumptions about the data. If the data at hand do not satisfy these assumptions, the resulting pa may be misleading.
