Explain thermal and signal fundamentals

Answer the following hardware fundamentals questions for a wearable sensor product: 1. Model a heat-transfer path as an equivalent thermal-resistance network. Explain how you would use that model to size or evaluate a module. 2. How do you choose a pull-up resistor for a digital line? 3. How do you choose an appropriate I2C bus frequency for multiple sensors in a compact device? 4. How can analog circuitry and PCB/layout practices be used to filter or reduce noise before sampling? 5. If you are given a short segment of sensor data, what basic analysis would you perform, and how would you interpret a box plot when looking for outliers, lot variation, or drift? Focus on first-principles reasoning and practical engineering trade-offs rather than memorized definitions.