Group 1 - The core idea emphasizes the importance of foundational knowledge in investment and fund selection, suggesting that solid fundamentals are crucial for successful investing [2] Group 2 - The article discusses how index sample adjustments can impact individual stock prices, highlighting that changes in component stocks may amplify short-term volatility [3] - It explains that when component stocks are adjusted, index funds typically modify their weights to minimize tracking error, which affects the stocks being added to the index [3]