Z-scores are a vital concept within Lean Six Sigma , enabling you to measure how far a value lies from the average of its dataset . Essentially, a z-score tells you the degree of standard deviation between a specific point and the average score. Higher z-scores denote the data point is above the average , while smaller z-scores indicate it's below.

The Chi-square test is a statistical method used to analyze the relationship between two or more categorical variables. It measures whether there is a significant difference between the observed and expected frequencies in a dataset. The test depends on the concept of chi-square, which represents the sum of squared differences between the observed