Six Sigma Green Belt Certification Practice Exam

Given a standard deviation of 2 and a specification limit range from 70 to 130, what is the ratio of the precision distribution to the precision total?

1. -0.20

2. 0.20

3. 5.00

4. -5.00

The correct answer is: 0.20

To determine the ratio of the precision distribution to the precision total, we first need to understand the concept of precision in the context of Six Sigma. Precision reflects the consistency of measurements, which can be quantified through the standard deviation. In this scenario, a standard deviation of 2 indicates that the data points tend to fall within two units of the mean value. The specification limits range from 70 to 130, which means we need to consider the total span (or range) of acceptable values. The total range, calculated as the upper specification limit minus the lower specification limit, is 130 - 70 = 60. The ratio of the precision distribution to the precision total is defined as the standard deviation divided by the total range (specification limits). Therefore, we can compute this ratio as follows: 1. The standard deviation is 2. 2. The total range is 60. The ratio can be calculated as: \[ \text{Ratio} = \frac{\text{Standard Deviation}}{\text{Total Range}} = \frac{2}{60} = \frac{1}{30} \approx 0.0333 \] However, the question might frame the ratio differently based on specific standards or scaling factors which