Quadratic trend occurs when:

Quadratic trend occurs when:

• A. The means increase linearly.
• B. The means in ordered conditions show one change in direction, producing a curved (U-shaped) line; at least three ordered conditions are required.
• C. The means decrease linearly.
• D. The means are constant across conditions.

Answer: (B)

Quadratic trend looks for curvature in how the means change across ordered conditions. Instead of a straight-line increase or decrease, the pattern bends once, creating a U-shaped (or inverted U) line. You need at least three ordered conditions to detect this curvature, because two points can only form a straight line. So a pattern where the means change direction once across the ordered levels best fits a quadratic trend. Linear increases or decreases, or no change at all, do not show this curvature.

Quadratic trend looks for curvature in how the means change across ordered conditions. Instead of a straight-line increase or decrease, the pattern bends once, creating a U-shaped (or inverted U) line. You need at least three ordered conditions to detect this curvature, because two points can only form a straight line. So a pattern where the means change direction once across the ordered levels best fits a quadratic trend. Linear increases or decreases, or no change at all, do not show this curvature.