Bias is the difference between the model’s predicted and actual values, indicating systematic errors due to simplistic assumptions.
High bias leads to underfitting, where the model does not capture the complexity of the data well and performs poorly on training and testing sets.
Low bias signifies the model accurately fits the training data by capturing underlying patterns and relationships.
Illustration: Trying to fit curve-shaped data points with a straight line leads to a simplistic model that misses most of the data points, showcasing the impact of bias-variance dilemma.