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1. Exploratory Data Analysis
1.3. EDA Techniques
1.3.3. Graphical Techniques: Alphabetic
1.3.3.26. Scatter Plot

1.3.3.26.7.

Scatter Plot: Sinusoidal Relationship (damped)

Scatter Plot Showing a Sinusoidal Relationship scatter plot showing a sinusoidal relationship
Discussion The complex relationship between X and Y appears to be basically oscillatory, and so one is naturally drawn to the trigonometric sinusoidal model:
    Y(i) = C + alpha*SIN(2*PI*omega*t(i) + phi) + E(i)
Closer inspection of the scatter plot reveals that the amount of swing (the amplitude alpha in the model) does not appear to be constant but rather is decreasing (damping) as X gets large. We thus would be led to the conclusion: damped sinusoidal relationship, with the simplest corresponding model being
    Y(i) = C + (B0+B1*t(I))*SIN(2*PI*omega*t(i) + phi) + E(i)
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