What is the acceptable range for a control if the mean is 130 g/L and the standard deviation is 2.0?

To determine the acceptable range for a control based on the mean and standard deviation, it is essential to apply the concept of statistical control limits. Typically, control limits in quality control charts are set at ±2 standard deviations from the mean.

Here, the mean is 130 g/L, and the standard deviation is 2.0 g/L. When calculating the control limits:

1. Calculate the lower limit: Mean - 2(Standard Deviation) = 130 - 2(2) = 130 - 4 = 126 g/L.

2. Calculate the upper limit: Mean + 2(Standard Deviation) = 130 + 2(2) = 130 + 4 = 134 g/L.

This gives us a control range of 126 g/L to 134 g/L.

The range of 126 to 134 is precisely the interval that aligns with one of the choices provided, which is option B. This means that for results to fall within acceptable limits, they must lie within this calculated range.

Understanding the application of mean and standard deviation in defining control limits is crucial for evaluating laboratory results, ensuring that they fall within expected parameters for reliability and accuracy in testing outcomes.