Hi all,

I'm having a problem in deciding how to perform a t-test on my descriptive statistics. I'm trying to find the motivations of Chinese infrastructure investment in three different regions Africa, Europe and One belt one road. Descriptive statistics should be presented for all countries and these regions separately but I'm confused how to do that? do I perform a one-sample, two-sample or paired t-test?

Below is the data extract of all countries combined where lnofdi is natural log of overseas infrastructure investment, lngdp is natural log of country gap and ln res is the natural log of natural resource exports.

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input str72 country int year float(lnofdi lngdp lnres)
"Afghanistan" 2005         0  22.55985          .
"Afghanistan" 2006         0  22.67737          .
"Afghanistan" 2007         0  23.01011          .
"Afghanistan" 2008         0 23.044725          .
"Afghanistan" 2009         0  23.24795 -1.9806697
"Afghanistan" 2010         0   23.4919 -1.2900953
"Afghanistan" 2011  5.991465 23.609755 -1.1848685
"Afghanistan" 2012         0  23.74547          .
"Afghanistan" 2013         0 23.732124          .
"Afghanistan" 2014         0  23.74934          .
"Afghanistan" 2015         0 23.678986   1.507562
"Afghanistan" 2016         0  23.69209  .11735813
"Afghanistan" 2017  5.347107 23.758955          .
"Algeria"     2005  6.697034 25.359915  4.5902495
"Algeria"     2006  8.781095  25.48567  4.5913815
"Algeria"     2007         0  25.62837   4.587998
"Algeria"     2008  5.075174 25.864935  4.5871253
"Algeria"     2009  8.009695 25.644785  4.5867243
"Algeria"     2010         0 25.805956  4.5812593
"Algeria"     2011  7.106606  26.02168  4.5793686
"Algeria"     2012  7.901007  26.06588   4.578637
"Algeria"     2013  7.489971 26.069206   4.573566
"Algeria"     2014  7.229839 26.088354  4.5637636
"Algeria"     2015  5.598422 25.834494   4.550027
"Algeria"     2016  8.116715  25.79248   4.545886
"Algeria"     2017         0         .          .
"Angola"      2005  7.512071  24.06378          .
"Angola"      2006   6.60665  24.45591          .
"Angola"      2007         0 24.825064  4.5889764
"Angola"      2008  8.083328   25.1562          .
"Angola"      2009  7.265429   25.0473  4.5912113
"Angola"      2010         0  25.13638   4.590789
"Angola"      2011  8.089482  25.36877   4.588808
"Angola"      2012  6.214608  25.45879  4.5925374
"Angola"      2013  7.659172 25.550884  4.5889072
"Angola"      2014  7.478735 25.565325   4.588818
"Angola"      2015  6.413459  25.35431  4.5881395
"Angola"      2016  8.104704 25.280685          .
"Angola"      2017  8.166216  25.54523          .
"Azerbaijan"  2005         0  23.30694  4.3587813
"Azerbaijan"  2006         0  23.76698  4.4535623
"Azerbaijan"  2007  5.347107   24.2213  4.4208193
"Azerbaijan"  2008  6.086775  24.61207  4.5785284
"Azerbaijan"  2009         0  24.51406   4.533747
"Azerbaijan"  2010         0  24.69172   4.549909
"Azerbaijan"  2011 4.6051702  24.91219  4.5532537
"Azerbaijan"  2012         0 24.967236  4.5427794
"Azerbaijan"  2013         0  25.02955  4.5376697
"Azerbaijan"  2014         0 25.044006  4.5342174
"Azerbaijan"  2015         0  24.69496  4.4771953
"Azerbaijan"  2016         0  24.35736   4.490126
"Azerbaijan"  2017         0  24.43067  4.5163217
"Bahrain"     2005         0   23.4939  4.5367546
"Bahrain"     2006         0  23.64131  4.5476346
"Bahrain"     2007         0  23.80196  4.5177712
"Bahrain"     2008         0  23.97018   4.456026
"Bahrain"     2009         0  23.85607   4.430391
"Bahrain"     2010         0 23.970274  4.5266333
"Bahrain"     2011         0  24.08283  4.5357018
"Bahrain"     2012         0 24.149134  4.4454975
"Bahrain"     2013         0  24.20572   4.348288
"Bahrain"     2014         0 24.231453   4.405266
"Bahrain"     2015         0 24.161304  4.3517857
"Bahrain"     2016         0  24.19376  4.3542657
"Bahrain"     2017         0  24.28735          .
"Bangladesh"  2005         0  24.96377  -.2544695
"Bangladesh"  2006         0 24.997416  .09207157
"Bangladesh"  2007         0  25.10043   .7178987
"Bangladesh"  2008         0  25.24104   .5525484
"Bangladesh"  2009  5.135798 25.352915   .7216684
"Bangladesh"  2010  6.633318  25.47062    .848006
"Bangladesh"  2011  6.672033  25.58027    .470242
"Bangladesh"  2012  6.536692  25.61629    .739724
"Bangladesh"  2013   6.64639 25.733835   .3717198
"Bangladesh"  2014  7.828038  25.87589          .
"Bangladesh"  2015  8.368693  25.99667  -.3096612
"Bangladesh"  2016  9.180912 26.123304          .
"Bangladesh"  2017  8.306472  26.24362          .
"Belarus"     2005         0  24.13136   3.559921
"Belarus"     2006         0  24.33295   3.655087
"Belarus"     2007  6.429719 24.536074   3.571639
"Belarus"     2008  5.799093 24.830256  3.6226616
"Belarus"     2009         0  24.61935   3.633932
"Belarus"     2010  6.887553  24.77021   3.341227
"Belarus"     2011  7.286192 24.846485   3.590348
"Belarus"     2012  5.991465  24.90814  3.6442685
"Belarus"     2013         0  25.04777   3.497674
"Belarus"     2014  5.828946 25.090355    3.52727
"Belarus"     2015  6.684612 24.756704   3.395893
"Belarus"     2016  6.745236  24.58867   3.079409
"Belarus"     2017         0  24.72041          .
"Belgium"     2005         0 26.682636  2.2639782
"Belgium"     2006         0 26.738966   2.435225
"Belgium"     2007         0 26.879866  2.3704205
"Belgium"     2008         0  26.97445    2.52924
"Belgium"     2009         0  26.90649  2.3230798
"Belgium"     2010         0 26.904417   2.522069
"Belgium"     2011         0  26.99048  2.6771014
"Belgium"     2012  5.560682 26.933634   2.716798
"Belgium"     2013         0  26.97887  2.7679825
end
format %ty year