Name: Cross-Validation Lab
Author: MySimulator

Model & data

Polynomial degree: 4 Noise level: 1.0 k (number of folds): 5

Results

CV mean validation MSE—

CV std across folds—

Single-split MSE (last try)—

Single-split range seen—

Every "try one split" click re-shuffles which 20% becomes the held-out set — watch how much that single number jumps around versus the k-fold average.

Per-fold validation error (bars) — dashed line = mean