数据为中国股市2015-2020的月回报面板数据。研究目的是讨论特定股票质量评价指标（FSCORE）对股票回报的预测能力。分析方法之一是用投资组合分析（已将样本依据质量指标分为了“Low FSCORE", "Mid FSCORE", "High FSCORE"，根据t-1的指标构建从t到t+1的投资组合），包括equally weighted 和 value-weighted两种计算方式。现在想求助如何用STATA产出如附件图片里类似的表格（求出每个分组下对应的return，并带有*和t值）？是该用什么命令？如下是目前STATA里按年份和质量分组进行了sort的前20个样本范例。请大家帮忙看看！谢谢！

[CODE]
* Example generated by -dataex-. To install: ssc install dataex
clear
input long Stkcd_n float Fyear str11 FSCORE_pf_lag1 float Mreted_yr
002377 2015 "Low FSCORE"  .08153618
002265 2015 "Low FSCORE"  .08193192
300077 2015 "Low FSCORE"  .05835925
600965 2015 "Low FSCORE"  .05137208
600225 2015 "Low FSCORE"  .05967558
002069 2015 "Low FSCORE"   .0438988
002276 2015 "Low FSCORE"  .18657374
601137 2015 "Low FSCORE"    .053691
002187 2015 "Low FSCORE" .073617086
002017 2015 "Low FSCORE"  .07074292
002671 2015 "Low FSCORE"  .10684358
600316 2015 "Low FSCORE"  .19151013
300150 2015 "Low FSCORE"  .06033175
600249 2015 "Low FSCORE"  .07299733
002196 2015 "Low FSCORE"   .0850179
002689 2015 "Low FSCORE"  .14178783
300245 2015 "Low FSCORE"  .07858308
002666 2015 "Low FSCORE"  .10441675
002519 2015 "Low FSCORE"  .06958055
000971 2015 "Low FSCORE"   .2317337
end
(Stkcd_n为股票代码，Fyear是时间变量，FSCORE_pf_lag1是year t-1的公司对应质量分组，Mreted_yr是t到t+1的对应月平均回报)