. do example.do

. * nwcommands tutorial 13: testing hypotheses about networks
. * Requires the core nwcommands.
. 
. * 1. Is a statistic unusual for a network of this size and density? (CUG test)
. nwwebuse florentine, nwclear

. nwsummarize flomarriage
--------------------------------------------------
   Network name:  flomarriage
   Network id:  2
   Directed: false
   Valued: false
   Two-mode: false
   Nodes: 16
   Selfloop: false
   Edges: 20
   Minimum value:  0
   Maximum value:  1
   Density:  .167
   Temporal: false

. nwcug flomarriage, stat(nwtriads ##net##) rname(transitivity) reps(500) seed(12345)
----------------------------------------
  Network: flomarriage
  Statistic: nwtriads ##net##/r(transitivity)
  Observed: .191
  Null mean (sd): .149 (.082)
  Reps: 500
  p (upper tail): .317
  p (lower tail): .697
  p (two-sided): .635
----------------------------------------

. nwcug flomarriage, stat(nwcomponents ##net##, generate(cc) replace silent) rname(components) reps(
> 500) seed(12345)
----------------------------------------
  Network: flomarriage
  Statistic: nwcomponents ##net##, generate(cc) replace silent/r(components)
  Observed: 2
  Null mean (sd): 1.986 (.812)
  Reps: 500
  p (upper tail): .707
  p (lower tail): .762
  p (two-sided): 1
----------------------------------------

. 
. * 2. Is one network related to another? (QAP correlation)
. nwwebuse glasgow, nwclear

. nwcorrelate glasgow1 glasgow2
----------------------------------------
  Network1 name: glasgow1
  Network2 name: glasgow2
----------------------------------------
    Correlation: .473

. nwcorrelate glasgow1 glasgow2, permutations(500)
----------------------------------------
  Network1 name: glasgow1
  Network2 name: glasgow2
----------------------------------------
    Correlation: .473
    P-value: .004

. 
. * 3. Does a covariate explain ties? (QAP regression)
. nwqap glasgow2 glasgow1 smoke1 sport1



Multiple Regression Quadratic Assignment Procedure

  Estimation            =  QAP
  Regression            =  logit
  Permutations          =  500
  Number of vertices    =  50
  Number of arcs        =  116

-------------------------------------------------
              glasgow2 |      Coef.    P-value
-----------------------+-------------------------
              glasgow1 |      3.653     .002
           same_smoke1 |       .514     .044
           same_sport1 |       .217     .345
                 _cons |     -4.125
-------------------------------------------------

. 
. * 4. The CUG test again, holding every family's number of marriages fixed
. nwwebuse florentine, nwclear

. nwcug flomarriage, stat(nwtriads ##net##) rname(transitivity) condition(degrees) reps(500) seed(12
> 345)
----------------------------------------
  Network: flomarriage
  Statistic: nwtriads ##net##/r(transitivity)
  Observed: .191
  Null mean (sd): .16 (.08)
  Reps: 500
  p (upper tail): .481
  p (lower tail): .798
  p (two-sided): .962
----------------------------------------

.