# Technical Analysis of Principal Component Analysis (PCA) Scatter Plots This image consists of three side-by-side scatter plots representing the distribution of "Experts" in a 2D feature space defined by Principal Components (PC1 and PC2). ## 1. Global Axis and Scale Information All three plots share the same coordinate system and scale: * **X-axis (PC1):** Ranges from approximately -800 to +800. Major tick marks are labeled at -500, 0, and 500. * **Y-axis (PC2):** Ranges from approximately -350 to +350. Major tick marks are labeled at -200, 0, and 200. * **Grid:** A light gray grid is present in the background of each plot to facilitate coordinate estimation. --- ## 2. Individual Plot Analysis ### Plot 1: Original Experts * **Legend Label:** Original Experts * **Marker Style:** Light red/pink circles with a darker outline. * **Data Distribution:** Shows the full set of approximately 16 data points. * **Cluster A (Top Left/Center):** A group of points located between PC1 [-300, 0] and PC2 [0, 300]. * **Cluster B (Bottom Right):** A group of points located between PC1 [200, 500] and PC2 [-200, -100]. * **Outliers:** One point at approx. (-800, -180) and two points near the bottom center at approx. (-300, -300) and (-150, -280). ### Plot 2: Surviving * **Legend Label:** Surviving * **Marker Style:** Solid blue circles. * **Data Context:** The "Original Experts" from Plot 1 are shown as faint, light-gray background points. * **Data Distribution:** Highlights a subset of approximately 8 points that have "survived." * These points are primarily concentrated in the center-top region (PC1 around -150 to +200, PC2 around -50 to +200). * One surviving point is located further down at approx. (200, -220). ### Plot 3: Merged * **Legend Label:** Merged * **Marker Style:** Green "x" symbols. * **Data Context:** The "Original Experts" from Plot 1 are shown as faint, light-gray background points. * **Data Distribution:** Highlights a subset of approximately 10 points that have been "merged." * **Cluster C (Center Right):** A group of points located between PC1 [150, 450] and PC2 [0, 100]. * **Cluster D (Bottom Right):** A group of points located between PC1 [100, 700] and PC2 [-280, -250]. * Notably, the "Merged" points occupy different spatial regions than the "Surviving" points, appearing more shifted toward the positive PC1 (right) and negative PC2 (bottom) directions. --- ## 3. Summary of Key Trends * **Spatial Separation:** The "Surviving" experts (blue) tend to cluster around the vertical axis (PC1 $\approx$ 0), while the "Merged" experts (green) are predominantly located in the right half of the plot (positive PC1). * **Data Reduction:** The second and third plots demonstrate a selection or transformation process where specific regions of the original expert distribution are categorized into "Surviving" or "Merged" status. * **Outlier Handling:** The extreme outlier at the far left (PC1 $\approx$ -800) is neither "Surviving" nor "Merged," as it remains gray in the subsequent plots.