Six Sigma Green Belt Certification Practice Exam

Which tool would you use to visually display the frequency of defects over time?

1. Scatter plot

2. Control chart

3. Flowchart

4. Histogram

The correct answer is: Control chart

A control chart is specifically designed to visually display data over time, making it ideal for monitoring the frequency of defects. This tool helps in identifying trends, shifts, or any unusual patterns in the data, as it plots the defect frequency against time along with control limits. These control limits allow for the observation of variance in the process, indicating whether it is stable and in control or if there are significant changes that require further investigation. In contrast, while a scatter plot is useful for showing relationships between two variables, it does not inherently reflect time series data. A flowchart is effective for mapping out processes and their steps but does not provide frequency data over time. A histogram represents the distribution and frequency of data points but does not specifically provide insights over time, making the control chart the most suitable choice for tracking the frequency of defects consistently in a time-frame context.