What type of error is characterized by some results being affected unpredictably?

Random error is characterized by variability in test results that cannot be attributed to a specific cause and is often unpredictable. This type of error can arise from a variety of sources, including fluctuations in the measurement process, variations in the sample, or environmental factors. Because it does not follow a systematic pattern, random error leads to results that may scatter around the true value, making it challenging to predict how individual test results will differ from one another.

In contrast, errors such as shifts and trends are systematic deviations that can be identified and potentially corrected. A shift represents a sudden change in test results over time, while a trend indicates a consistent increase or decrease over time. Kurtosis, on the other hand, is a statistical term referring to the shape of the distribution of data, which does not directly relate to the concept of error in testing.

Understanding the nature of random error is crucial for laboratory professionals, as it helps in the interpretation of test results and in determining the reliability of measurements. It also underscores the importance of quality control in laboratory practices to minimize such unpredictable influences on test outcomes.