📈 散点图生成器（含趋势线和 R²）Scatter Plot Maker
粘贴两列数值（X 和 Y，可加第三列分组）即可生成散点图：可添加线性趋势线并显示方程和 R²、设置坐标轴标题、对数坐标，下载 PNG。数据在本地处理。Paste two columns of numbers (X and Y, with an optional third column for groups) to draw a scatter plot — add a linear trend line with its equation and R², axis titles and log scales, then download a PNG. Data stays on your device.
使用说明与常见问题How-to & FAQ
「散点图生成器（含趋势线和 R²）」是什么？What is the Scatter Plot Maker tool?
粘贴两列数值（X 和 Y，可加第三列分组）即可生成散点图：可添加线性趋势线并显示方程和 R²、设置坐标轴标题、对数坐标，下载 PNG。数据在本地处理。Paste two columns of numbers (X and Y, with an optional third column for groups) to draw a scatter plot — add a linear trend line with its equation and R², axis titles and log scales, then download a PNG. Data stays on your device.
如何使用「散点图生成器（含趋势线和 R²）」？How do I use the Scatter Plot Maker tool?
在「散点图生成器（含趋势线和 R²）」中，按需设置「标题」、「X 轴标题」、「Y 轴标题」、「点大小」、「导出背景」等选项，然后点击「下载 PNG」按钮即可。In the Scatter Plot Maker: Set "Title", "X axis title", "Y axis title", "Point size", "Export background", then click "Download PNG".
数据怎么输入？How do I enter data?
每行一个点：第一列 X，第二列 Y，可选第三列为分组名称（不同分组用不同颜色）。可以用逗号、Tab 或分号分隔，直接从 Excel 复制两列粘贴即可；只有当第一行的前两列都是文字时，才把它当作坐标轴标题；第一行缺少 X 或 Y 会报错，不会被悄悄丢掉。数字中的千分位逗号和末尾的 % 会被去掉（50% 读作 50），用逗号分隔时带千分位的数字要用英文双引号括起来（"1,200"）。每行最多 3 列。点大小可填 1–20。One point per line: X in the first column and Y in the second, with an optional third column naming a group (each group gets its own colour). Commas, tabs or semicolons all work, so you can paste two columns from Excel. The first row is used for the axis titles only when both of its first two cells are text; a first row missing X or Y gives an error instead of being dropped. Thousands commas and a trailing % are removed (50% reads as 50); with comma separators, put numbers with thousands commas in double quotes ("1,200"). Each line can have at most 3 columns, and the point size can be 1–20.
趋势线和 R² 是怎么算的？How are the trend line and R² calculated?
用最小二乘法拟合 y = mx + b（对所有点，不分组）。R² = 1 − 残差平方和 / 总平方和，表示 Y 的变化有多少比例能被 X 线性解释（所有 Y 都相同时 R² 没有定义，显示为 —）；计算前先减去平均值并缩放，非常大或非常小的数值也不会溢出；r 是皮尔逊相关系数。示例数据（身高与体重）的 R² 约为 0.988。Least squares fits y = mx + b to all points (ignoring groups). R² = 1 - residual sum of squares / total sum of squares — the share of Y's variation explained linearly by X (undefined, shown as —, when every Y is the same). Values are centred and scaled first, so very large or very small numbers do not overflow; r is Pearson's correlation. The sample height and weight data gives R² of about 0.988.
什么时候用对数坐标？When should I use log scales?
数据跨越多个数量级（如 1 到 100 万）时，对数坐标能让点分布更清楚，指数关系会显示为直线。对数坐标要求数值都大于 0。注意趋势线仍按原始数值的线性回归计算。When data spans several orders of magnitude (say 1 to 1,000,000), log scales spread the points out and show exponential relationships as straight lines. All values must be above 0. The trend line is still the linear regression on the raw values.
「散点图生成器（含趋势线和 R²）」免费吗？需要注册吗？Is the Scatter Plot Maker free? Do I need an account?
「散点图生成器（含趋势线和 R²）」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Scatter Plot Maker is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.