Google Data Analytics Professional Certification Practice Test

What does statistical power measure?

1. The size of the sample

2. Accuracy of data entry

3. The probability of obtaining meaningful test results

4. The method of sorting data

The correct answer is: The probability of obtaining meaningful test results

Statistical power is fundamentally about the likelihood that a statistical test will detect an effect when there is indeed an effect to be detected. It specifically measures the probability of correctly rejecting the null hypothesis when it is false, indicating that the test is capable of identifying true effects in the data. Higher statistical power means a greater chance of detecting a meaningful difference or relationship in the data if one exists, which is crucial in hypothesis testing. While the size of the sample influences statistical power—larger samples typically increase power—the figure itself represents more than just sample size alone. Similarly, accuracy of data entry and methods of sorting data do not pertain to the concept of power; they relate to data quality and management processes, respectively. Therefore, the precise measurement of the probability of obtaining meaningful test results makes this option the correct choice.