Dear Avril
I think you will find that predict.lm returns a matrix not a data frame.
I find str() useful when R does things I did not expect or quite understand.
Michael
On 10/08/2015 09:20, alc wrote:
Dear all,
I'm wondering how can I access the confidence interval values ('upr' and
'lwr' values) produced by the 'predict' function. For example, I fitted
a linear regression line using:
fit <- lm(y ~ x)
I then wanted to calculate a 95% confidence interval for the line, and
did this using:
ci <- predict(fit, data.frame(x), interval="confidence")
I see that the 'ci' object has 'upr' and 'lwr' variables stored in it,
but am not sure how to access them properly.
I find I can do it using:
upper <- as.data.frame(ci)$upr
lower <- as.data.frame(ci)$lwr
However, I'm wondering is there a more 'proper' way to do it in R? I
find that things like ci$upr don't seem to work, but am not sure what's
the right way?
Kind Regards,
Avril
--
Michael
http://www.dewey.myzen.co.uk/home.html
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