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st: RE: AW: RE: AW: AW: RE: -ciplot- -eclplot- combine with box-options?


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: AW: RE: AW: AW: RE: -ciplot- -eclplot- combine with box-options?
Date   Mon, 10 May 2010 11:31:25 +0100

My comment was a lament, not a reproach. I'll look at the help for
-stripplot- to make it clearer that -by()- is an easy alternative to
-over()-. 

In return, I am not clear what you mean by better interpretable graphs
than those generated with -by()-. 

Nick 
n.j.cox@durham.ac.uk 

Kaulisch, Marc

Dear Nick,

Thanks for the follow up clarifing opportunities with -stripplot-. I am
not as much into Stata that I can adhoc find solutions for two
nice-to-haves I would like. 1) Avoid a composite variable for including
two categorical variables (comparing sex by agegroup). 2) Better
interpretable graphs than those generated with by().

I might miss features of -stripplot- or Stata again.

. sysuse bpwide, clear

1) Example with boxplot
. graph hbox bp_before bp_after , over(sex, label(labs(vsmall)))
over(agegrp, label(labs(vsmall)) sort(1) descending)

2) Example with Confidence-intervals:

. tempfile tf1 tf2
. statsby mean1=r(mean) ub1=r(ub) lb1=r(lb) N1=r(N), by(agegrp)
saving(`tf1'): ci bp_before
. statsby mean2=r(mean) ub2=r(ub) lb2=r(lb) N2=r(N), by(agegrp)
saving(`tf2'): ci bp_after
. dsconcat `tf1' `tf2'
. generate axis = 6 if agegrp == 3 & sex == 0
. replace axis = 5 if agegrp == 3 & sex == 1
. replace axis = 4 if agegrp == 2 & sex == 0
. replace axis = 3 if agegrp == 2 & sex == 1
. replace axis = 2 if agegrp == 1 & sex == 0
. replace axis = 1 if agegrp == 1 & sex == 1
. la de laxis 6 "60+ Male" 5 "Female" 4 "46-59 Male" 3 "Female" 2 "30-45
Male" 1 "Female"
. la val axis laxis
. twoway scatter  axis mean1 || rcap ub1 lb1 axis, hori || scatter  axis
mean2 || rcap ub2 lb2 axis, hori , ///
			ylabel(1(1)6, labs(vsmall) nogrid val
angle(hori))			///	
			ytitle("")
///
			legend(label(1 "Mean bp_before") label(2 "CI
bp_before") ///
			label(3 "Mean bp_after") label(4 "CI bp_after")
size(vsmall) rows(2) span)
			

3) Stripplot (!?) with Confidence intervals:
* Generate axis as in solution (2)
. stripplot bp_before bp_after , by(axis, compact) vertical bar
boffset(0) ms(none) xsc(r(0.8 2.2))

Nick Cox

It's a pity that Marc missed a (simpler) solution with -stripplot- that
requires no dataset manipulation at all. 

sysuse bpwide 

stripplot bp_before bp_after , by(sex, compact) stack vertical bar
height(0.2)

gets you there directly. 

If you really want only the c.i. bars, so that the data points are
suppressed, that's perverse, but you can do it too: 

stripplot bp_before bp_after , by(sex, compact) vertical bar boffset(0)
ms(none) xsc(r(0.8 2.2))

In short, -stripplot- for two or more variables and two or more groups
requires -by()- not -over()-. As program writer, I saw no point trying
to re-create a complicated set-up when -by()- does it for you for free. 

Nick
n.j.cox@durham.ac.uk 

Kaulisch, Marc

Okay, it seems that -statsby- does the trick together with -dsconcat-
(ssc).

Preliminary without labels etc:

sysuse bpwide
tempfile tf1 tf2
statsby mean1=r(mean) ub1=r(ub) lb1=r(lb) N1=r(N), by(agegrp)
saving(`tf1') subsets total: ci bp_before statsby mean2=r(mean)
ub2=r(ub) lb2=r(lb) N2=r(N), by(agegrp)
saving(`tf2') subsets total: ci bp_after dsconcat `tf1' `tf2'
twoway rcap ub1 lb1 agegrp || scatter mean1 agegrp || rcap ub2 lb2
agegrp || scatter mean2 agegrp 

Kaulisch, Marc

Nick,

Thanks a lot for this extensive answer. I learn a lot. I haven't had
time yet to go deeper in the opportunities to work with statsby (will do
this later). But experimenting with -stripplot- I come very early to an
end...

I would like to create a graph such as
. sysuse bpwide
. graph hbox bp_before bp_after, over(sex) over(agegrp), sort(1)
descending)

But I do not want a boxplot but a ci-bar as in stripplot...

-stripplot- does not allow two vars with over.

. ciplot bp_before bp_after, by(agegrp)
looks closer to my interest...

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