A Study of Happy Planet Index.

. webuse set "https://raw.githubusercontent.com/kho777/data-visualization/master
> /data"
(prefix now "https://raw.githubusercontent.com/kho777/data-visualization/master/
> data")

. webuse "hpi2016dataonly", clear

Taking the log of GDP Per capita to make the variable more linear.

. gen lgdp=log(GDPcapitaPPP)

. label variable lgdp "GDP Per Capita (logged)"

Create multiple variables for plots of Happy Planet Index using Region. Use the label statements to clean and shorten the variable labels for legend

. separate HappyPlanetIndex, by(Region) shortlabel

              storage   display    value
variable name   type    format     label      variable label
--------------------------------------------------------------------------------
HappyPlanetIn~1 double  %10.0g                Region == Americas
HappyPlanetIn~2 double  %10.0g                Region == Asia Pacific
HappyPlanetIn~3 double  %10.0g                Region == Europe
HappyPlanetIn~4 double  %10.0g                Region == Middle East and North
                                                Africa
HappyPlanetIn~5 double  %10.0g                Region == Post-communist
HappyPlanetIn~6 double  %10.0g                Region == Sub Saharan Africa

. lab var HappyPlanetIndex1 "Americas"

. lab var HappyPlanetIndex2 "Asia Pacific"

. lab var HappyPlanetIndex3 "Europe"

. lab var HappyPlanetIndex4 "Middle East and North Africa"

. lab var HappyPlanetIndex5 "Post-communist"

. lab var HappyPlanetIndex6 "Sub Saharan Africa"

Explore relationship between HPI and GDP Per Capita

Scatter plot to show the relationship

. scatter HappyPlanetIndex? lgdp, ytitle(Happy Planent Index)

. regress HappyPlanetIndex lgdp 

      Source |       SS           df       MS      Number of obs   =       140
-------------+----------------------------------   F(1, 138)       =      9.28
       Model |  469.252954         1  469.252954   Prob > F        =    0.0028
    Residual |  6974.55558       138  50.5402578   R-squared       =    0.0630
-------------+----------------------------------   Adj R-squared   =    0.0562
       Total |  7443.80853       139  53.5525794   Root MSE        =    7.1092

------------------------------------------------------------------------------
HappyPlane~x |      Coef.   Std. Err.      t    P>|t|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
        lgdp |     1.2505   .4103919     3.05   0.003     .4390302    2.061969
       _cons |   15.65245    3.58156     4.37   0.000     8.570619    22.73428
------------------------------------------------------------------------------

The regression shows that for every unit increase in GDP Per Capita (logged), a 1.2505 unit increase in Happy Planet Index is predicted.