Random graphs (144): Automatically labeling figures with letters

// Open ESS round 5
use agea stflife cntry if inlist(cntry, "DE", "GB", "NL", "SE") using "ESS5e03_4.dta", clear

// Country variable
kountry cntry, from(iso2c)
rename NAMES_STD country

// Restrict to complete cases
keep if !missing(agea, stflife, cntry)

// Center age
qui sum agea, detail
replace agea = `r(p99)' if agea > `r(p99)' & !missing(agea)
bys country: center agea, gen(age)
drop agea
label var age "Age (centered)"

// Letters
tokenize "`c(ALPHA)'"
local i 1

levelsof country, local(country)

foreach z of local country {
  qui sum age if country == `"`z'"', detail 
  foreach x of numlist 10 25 50 75 90 {
    local x`x': di %9.1f r(p`x')
    di `x`x''
  }
  qui regress stflife c.age##c.age if country == `"`z'"'
  
  qui margins, at(age = (`x10' `x25' `x50' `x75' `x90'))
  marginsplot, title(`"{bf:``i''} `z'"') ///
               ytitle("Life satisfaction" "(predicted)") ///
               xtitle("Age (percentiles)") ///
               xlabel(`x10' "10th" ///
                      `x25' "25th" ///
                      `x50' "50th" ///
                      `x75' "75th" ///
                      `x90' "90th") ///
               ylabel(, format(%6.1f)) ///
               recastci(rarea) ciopts(color(gs10)) ///
               name("``i''", replace) nodraw
  local ++i
}

graph combine A B C D, col(2) ycommon

Random graphs (48): Interaction plot with overlaid data points

// Simulate data
clear
set seed 1
set obs 500

generate  e  = 0 + (500 - 0) * runiform()     // To generate random variates over the
generate  x1 = 0 + (800 - 0) * runiform()     // interval [a,b), a+(b-a)*runiform()

generate  x2 = round(0 + (1 - 0) * runiform()) // Binary variable
generate  y  = (x1 + x2 + (x1*x2) + e) / 1000

// Calculations for Aiken & West (1991) style plot
regress y c.x1##x2

qui sum x1
local x1_minsd = r(mean) - (2*r(sd))
local x1_mean  = r(mean)
local x1_plusd = r(mean) + (2*r(sd))


// Calculate predicted values for plot
margins, at(c.x1 = (`x1_minsd' `x1_mean' `x1_plusd') ///
            c.x2 = (0 1)) vsquish
// Plot
qui marginsplot, recastci(rarea) ciopts(color(gs10)) ///
   title("Interaction plot with overlaid data points") ///
   ytitle("y") ///  
   ylabel(, format(%6.1f)) ///
   xtitle("") ///
   plotopts(msymbol(none)) ///        // Turn off markers
   plot1opts(lpattern(longdash)) ///  // Define line types here
   plot2opts(lpattern(solid)) ///
   addplot(scatter y x1 ///
         , symbol(o) ///
           xlabel(`x1_minsd' "-2 SD" ///       // The addplot seems to override
                  `x1_mean' "Average x1" ///   // the regular axis label 
                  `x1_plusd' "+2 SD") ///      // command
           legend(subtitle(x2) ///             // And the legend command
                  order(3 "x2 = 0" 4 "x2 = 1" 2 "95 % CI"))) ///    
   legend(pos(5) ring(0)) ///                  // But not completely
   name(plot, replace)