Lean Six Sigma Certification

The Mann-Whitney U test, also known as the Wilcoxon rank-sum test, is a non-parametric statistical test used in Six Sigma to compare differences between two independent groups. It assesses whether the distribution of ranks in one group is significantly different from the other, making it suitable for ordinal data or when the assumptions of the […]

An F-test is a statistical method used in Six Sigma to compare the variances of two or more groups to determine if they are significantly different. It is commonly used in analysis of variance (ANOVA) to test the null hypothesis that the variances are equal. The F-test calculates the F-ratio, which is the ratio of […]

ANOVA (Analysis of Variance) is a statistical tool used in Six Sigma to compare the means of three or more groups to determine if there are any statistically significant differences among them. It assesses the impact of one or more factors by comparing the variance within groups to the variance between groups. ANOVA tests help […]

A z-test is a statistical method used in Six Sigma to determine whether there is a significant difference between sample and population means, or between the means of two samples. It is applicable when the population variance is known and the sample size is large (typically over 30). The z-test calculates a z-score, which represents […]

Hypothesis testing is a fundamental Six Sigma tool used to make data-driven decisions by evaluating assumptions about a population parameter. It involves formulating a null hypothesis (H0) and an alternative hypothesis (H1). The null hypothesis represents a statement of no effect or no difference, while the alternative hypothesis represents the effect or difference you aim […]

Z tables, or standard normal distribution tables, are Six Sigma tools used to find the probability of a statistic occurring within a standard normal distribution. They provide the cumulative probability associated with each z-score, which represents the number of standard deviations a data point is from the mean. Z tables are essential for calculating probabilities, […]

A scatter plot is a Six Sigma tool that visually displays the relationship between two variables. Each point on the plot represents a pair of values, with one variable on the x-axis and the other on the y-axis. By analyzing the pattern of points, you can identify correlations, trends, and potential causative relationships. Scatter plots […]

A run chart is a Six Sigma tool used to display data points over time, highlighting trends and patterns in process performance. It plots individual data points on the y-axis against time on the x-axis, providing a visual representation of process behavior. Run charts help identify shifts, trends, and cycles in data, making it easier […]

A stem and leaf plot is a Six Sigma tool used to display quantitative data in a graphical format, similar to a histogram but preserving the original data values. It organizes data points into “stems” (the leading digits) and “leaves” (the trailing digits). This format helps visualize the distribution, central tendency, and spread of the […]

Skewness and kurtosis are statistical measures used in Six Sigma to describe the shape of a data distribution. Skewness measures the asymmetry of the distribution. Positive skewness indicates a distribution with a longer tail on the right, while negative skewness indicates a longer tail on the left. A skewness of zero indicates a symmetrical distribution. […]

A box plot, also known as a box-and-whisker plot, is a Six Sigma tool used to visualize the distribution of a dataset. It displays the dataset’s minimum, first quartile, median, third quartile, and maximum values, highlighting the spread and central tendency of the data. The box represents the interquartile range (IQR), while the whiskers extend […]

A histogram is a powerful Six Sigma tool used to visualize the distribution of a dataset. It displays data in the form of bars, where each bar represents the frequency of data points within a specific range or bin. By showing the shape, spread, and central tendency of the data, histograms help identify patterns, trends, […]