threshold distribution

On Sun, 2009-04-05 at 01:13 -0400, jim holtman wrote:

Here is what I get from using 'fitdistr' in R to fit to a lognormal.
The resulting density plot from the distribution seems to be a reason
match to the data.

x <- scan()

1: 0.80010 0.72299 0.69893 0.99597 0.89200 0.69312 0.73613 1.13559
9: 0.85009 0.85804 0.73324 1.04826 0.84002
14: 1.76330 0.71980 0.89416 0.89450 0.98670 0.83571 0.73833 0.66549
22: 0.93641 0.80418 0.95285 0.76876 0.82588
27: 1.09394 1.00195 1.14976 0.80008 1.11947 1.09484 0.81494 0.68696
35: 0.82364 0.84390 0.71402 0.80293 1.02873
40:
Read 39 items

plot(density(x))
library(MASS)
fitdistr(x, 'lognormal')

? ? ?meanlog ? ? ? ?sdlog
? -0.13480636 ? ?0.19118861
?( 0.03061468) ( 0.02164785)

lines(dlnorm(x, -.1348, .1911), col='red')

Hi Jim

I agree with your solution but my plot result not fine.
I obtain same result.

fitdistr(x, 'lognormal')

? ? meanlog ? ? ? ?sdlog
?-0.13480636 ? ?0.19118861
?( 0.03061468) ( 0.02164785)

In plot when I use points (blue) and curve (green) the fit o lognormal
and density(data) is fine but when I use lines (red) the fit is bad (in
attach I send a PDF of my output)

Do you know why this ?happen?

Thanks in advance

--
Bernardo Rangel Tura, M.D,MPH,Ph.D
National Institute of Cardiology
Brazil

P.S. my script is

x <- scan()
0.80010 0.72299 0.69893 0.99597 0.89200 0.69312 0.73613 1.13559
0.85009 0.85804 0.73324 1.04826 0.84002
1.76330 0.71980 0.89416 0.89450 0.98670 0.83571 0.73833 0.66549
0.93641 0.80418 0.95285 0.76876 0.82588
1.09394 1.00195 1.14976 0.80008 1.11947 1.09484 0.81494 0.68696
0.82364 0.84390 0.71402 0.80293 1.02873

require(MASS)
fitdistr(x, 'lognormal')
pdf("adj.pdf")
plot(density(x))
lines(dlnorm(x, -.1348, .1911), col='red')
points(x,dlnorm(x, -.1348, .1911), col='blue')
curve(dlnorm(x, -.1348, .1911), col='green',add=T)
dev.off()