Certified Pulmonary Function Technologist (CPFT) Practice Exam

What does a standard deviation indicate in measurement accuracy?

1. The variability of results from the mean

2. The average accuracy of the measurements

3. The number of measurements taken

4. The range of acceptable results

The correct answer is: The variability of results from the mean

A standard deviation is a crucial statistical measure that indicates how much individual measurements within a data set vary from the mean (average) of that data set. When measurements are taken, there is often some level of variability due to various factors such as instrument precision, operator technique, and patient variability in pulmonary function tests. A lower standard deviation suggests that the measurements are closely clustered around the mean, indicating higher consistency and reliability. Conversely, a higher standard deviation reflects greater variability, suggesting that the measurements differ significantly from one another. This understanding of standard deviation as a measure of variability is essential in interpreting data accurately in pulmonary function testing. It allows healthcare professionals to assess the degree of consistency in the tests performed and can inform them about the stability or reliability of the results. Therefore, recognizing standard deviation helps in evaluating the precision of measurements in clinical practice.