Participants are not allowed to modify the training procedure.

It's been nearly 20 years since Apple was this untethered from its tech peers, giving investors an appealing alternative to the artificial intelligence-fueled volatility that has gripped most other corners of the stock market in recent weeks. Apple's 40-day correlation to the Nasdaq 100 Index tumbled to 0.21 last week, the lowest since 2006, according to data compiled by Bloomberg. Its correlation with the benchmark has been on the decline since May, when it reached 0.92, as Apple's decision to mostly sit out the AI arms race has turned it into an outlier compared with many of its rivals. A correlation of 1 means the two securities are moving in perfect unison, while a reading of -1 signals they are moving opposite each other. "Apple's lack of correlation is 100% a positive right now," said Art Hogan, who helps oversee $25 billion as chief market strategist at B. Riley Wealth.

Decision trees are a fundamental workhorse in machine learning. Their logical and hierarchical structure makes them easy to understand and their predictions easy to explain.

Although freely accessible, it is provided in individual files for each year, and is difficult to combine in order to analyze spatial or temporal trends.