中文辅助说明
这个工具把组距数据中位数插值拆成可观察的步骤：先累加频数、确定中位数所在组，再把组界和累积频数放进比例图。学习模式帮助你看懂公式中每个数从哪里来；练习模式则让你亲自填写累积频数、选出中位数组并完成插值。
Your interpolation table
Match a position in cumulative frequency to a value of x
Read cumulative frequency on the left of the line and the corresponding value of x on the right.
Median position:
Build the proportion
Linear interpolation