Question: Describe the structure of the error table proposed by Andrew Ng for evaluating a model like the cat image detector, including the axes and their respective components. Additionally, explain why an engineer might fill in the additional entries in this table.

Sample answer: The error table is structured with data distributions on the x-axis and error types on the y-axis. For the cat image detector, the x-axis contains two different data distributions. The y-axis contains three specific error types: human-level error, error on trained examples, and error on untrained examples. Filling in the additional entries in this table is valuable because it can provide deeper diagnostic insight into how the algorithm behaves differently across the two data distributions.

Key points:

• The x-axis represents two different data distributions.
• The y-axis represents human-level error, error on trained examples, and error on untrained examples.
• Filling additional entries provides diagnostic insight into the algorithm's behavior across distributions.

Rubric: A strong answer should accurately identify the components of the x and y axes (two distributions and three specific error types) and mention that additional entries provide insights into the algorithm's performance across distributions.