What statistical tool is commonly used in Six Sigma for data analysis?

Control charts are essential tools in Six Sigma used for monitoring and controlling processes over time. They allow teams to visualize how a process varies and whether it remains stable or exhibits trends or shifts that may indicate potential issues. By plotting data points in a time-ordered sequence, control charts help businesses distinguish between common cause variation (natural fluctuations in a process) and special cause variation (indicating that something has changed in the process).

These charts include upper and lower control limits, which are statistically derived thresholds that help assess whether a process is functioning within an acceptable range. When data falls outside these limits, it signals the need for investigation and possible corrective action, supporting decision-making aimed at process improvement. Thus, control charts are crucial for maintaining quality and ensuring that processes remain efficient and effective over time.

While histograms, Pareto charts, and scatter plots are also useful statistical tools within Six Sigma, each serves different purposes. Histograms display the frequency distribution of data, Pareto charts help identify the most significant factors in a data set, and scatter plots illustrate relationships between two variables. However, for ongoing process control specifically, control charts are the most commonly used tool.