Graphing and Analysis

考纲要求

• Plot a graph following conventions required for Paper 3
• Show error bars in both directions
• Draw straight line of best fit and worst acceptable line
• Determine gradient and y-intercept
• Estimate absolute uncertainty in gradient and y-intercept

常见题型

• Plotting graphs with error bars
• Best fit and worst acceptable lines
• Gradient determination with uncertainty
• y-intercept determination

核心公式

• $\text{gradient} = \frac{\Delta y}{\Delta x}$
• $\text{uncertainty in gradient} = |\text{best gradient} - \text{worst gradient}|$
• $y\text{-intercept}$: substitute $(x, y)$ and gradient into $y = mx + c$

常见错误

• Points not accurate to half a small square
• Error bars asymmetrical or missing
• WAL doesn't go through all error bars
• Points too close for gradient calculation