Three classification models were trained on a dataset of previous bank transactions with the goal of detecting fraudulent transactions. The first model (M1), which is complex, has a training error of 0.0034. The second model (M2), which is simpler, has a training error of 0.0047. The third model (M3), which is the simplest, has a training error of 0.1251. Which model would be the best one to use for classifying future transactions?

You trained a model to predict stock market prices. Your model performs well on your dataset, but performs poorly on a different dataset. How can you improve your model?

You want to train a model for detecting stones that contain gold. A mining company has a dataset of 5 million stone images, of which only 500 contain gold. What is the best measure to evaluate your model if you designate stone images with gold as the positive class?

You have a dataset of 5,000 audio files, and you want to train a model to detect music files within the dataset. How would you validate the performance of your classifier?

You are given a dataset of cars and asked to train a decision tree to classify the cars into two classes: Luxury and Sports. If a leaf node contains 100 cars, which case would provide better performance? (L represents the Luxury class, and S represents the Sports class.)

What is an underlying assumption of Naive Bayes Classification?

You want to train a model for detecting bald eagles. National Geography provides you a dataset of 1 million bird images, of which only 200 are bald eagles. What is the best measure to evaluate your model if you designate bald eagles as the positive class?

Compute the cosine similarity and correlation coefficient between feature vectors X and Y: X = (4, 2, 3, 3) Y = (1, 3, 5, 7)

You are given a dataset of agricultural products and asked to train a decision tree to classify the products into two classes: Fruits and Vegetables. If a leaf node contains 100 products, which case would provide better performance? (F represents the Fruits class, and V represents the Vegetables class.)

Your company recently introduced a new service, and you decide to conduct a survey among its 30 million users to get their feedback on the new service. Based on data mining techniques, which users will you survey?