NO.PZ2015120604000120
问题如下：
Which of the following most correctly describes the sample of equity ratios of 50 U.K. banks at fiscal year 2017?
选项：
A.Interval estimate.
B.Cross-sectional data.
C.Time-series data.
解释：
B is correct.
Because the data for the sample are collected at the same point of time, So it is the example of the cross-sectional data.
因为样本的数据是在同一时间点采集的，所以本题所描述的例子为横截面数据
一个时间点能是一年吗？为什么不能是2017年每天或者每个月ratio的变化？cross-sectional不需要其他类似数据对比吗？
