中考数学：数据图表与抽样

A middle-school mathematics practice set on data charts and sampling: population and sample, sampling methods, frequency/statistical charts, variance, and reading data trends.

• Identify sample size from a survey description
• Judge which sampling method is more representative and random
• Convert a pie-chart central angle to its corresponding percentage
• Understand that a uniform data shift does not change variance

面向中国中考数学的原创练习：总体与样本、抽样方法、条形图、折线图、扇形图、频数与频率、方差和数据趋势判断。