Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.

# st: RE: CDF log-normal and histogram

 From Nick Cox To "'statalist@hsphsun2.harvard.edu'" Subject st: RE: CDF log-normal and histogram Date Fri, 11 Feb 2011 19:57:28 +0000

```Not the graph I would use in that territory.

See -lognfit- (Stephen Jenkins, SSC) and -qlogn- from -qpfit- (SSC) for more critical choices.

But in terms of what you ask, I don't know what "doesn't work" means in your case.

Consider

sysuse auto, clear
gen ln_price = ln(price)
su ln_price

distplot price, ///
addplot(function normal((ln(x) - `r(mean)')/`r(sd)'), lp(dash) ra(1 16000)) ///
legend(order(1 "delicious data" 2 "mad model")) yla(, ang(h))

If you want to fit the distribution in other ways, plug in your parameter estimates accordingly.

Here's a stab at a histogram too:

sysuse auto, clear
gen ln_price = ln(price)
su ln_price

distplot price, ///
addplot(function normal((ln(x) - `r(mean)')/`r(sd)'), lp(dash) ra(1 16000) ///
|| histogram price, fraction bfcolor(none) width(2000)) ///
legend(order(1 "delicious data" 2 "mad model")) yla(, ang(h))

In terms of giving references to user-written stuff as requested:

-distplot- is from SJ.
-dpplot- is from SJ.

Authors not named are me.

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

Beatrice Crozza

I want to have a graph which combine the histogram of frequencies for
my variable and on the same graph an empirical CDF of data and a
fitted CDF (log-normal)

I can do the histogram in this way:
histogram var1, freq

To see if my variable follows a log-normal I do:
dpplot var1, dist(log-normal)

The CDF of my variable in this way:
distplot var1,

How can I combine the histogram with the empirical CDF and the fitted
CDF (log-normal)?

I tried with twoway but it doesn't work.

Thank you very much for your help.

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/
```