what is a statistical assumption
Assumptions for Statistical Tests. As we can see throughout this website, most of the statistical tests we perform are based on a set of assumptions. When these assumptions are violated the results of the analysis can be misleading or completely erroneous. Typical assumptions are:1  Normality: Data have a normal distribution (or at least is symmetric).s we can see throughout this website, most of the statistical tests we perform are based on a set of assumptions. When these assumptions are violated the results of the analysis can be misleading or completely erroneous. Typical assumptions are: 1  Normality: Data have a normal distribution (or at least is symmetric).