Which term describes six consecutive measurements rising or falling and may cross the mean?

• A. Random Error
• B. Active Error
• C. Trend
• D. Systematic Error

Answer: (C)

A trend is a persistent directional movement in measurements over time. When six consecutive results consistently rise or fall, it shows a drift in the process rather than random fluctuation. This pattern can cross the mean, such as values creeping from below the target toward above it, signaling a potential issue with the instrument, calibration, or method that needs investigation. This differs from random error, which fluctuates unpredictably around the mean with no overall direction, and from systematic error, which is a constant bias affecting all measurements in the same way. The key idea is the ongoing drift in one direction, not just isolated deviations.