Displaying 4 results from an estimated 4 matches for "lagx".
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lag
2005 Feb 18
9
Using time series and lm
...iate time series containing NA values.
I want to compute a linear regression and obtain a time serie for both
residuals and fitted values. I have tried the trick ts.intersect,
without success.
Could you help me out of this?
####
Example:
y<-ts(1:10+rnorm(10))
x<-ts(1:10)
datats<-cbind(y,lagx=lag(x))
Notice the datats could come directly from an imported file, that is
why I did not use ts.intersect(y,lagx=lag(x))
fit<-lm(y~lagx,data=datats,na.action=na.omit)
but how do I get a time serie of residuals instead of a vector residuals(fit)?
######
Matthieu Cornec
2005 Mar 05
4
How to use "lag"?
Is it possible to fit a lagged regression, "y[t]=b0+b1*x[t-1]+e",
using the function "lag"? If so, how? If not, of what use is the
function "lag"? I get the same answer from y~x as y~lag(x), whether
using lm or arima. I found it using y~c(NA, x[-length(x)])). Consider
the following:
> set.seed(1)
> x <- rep(c(rep(0, 4), 9), len=9)
> y <-
2011 Aug 04
2
Efficient way of creating a shifted (lagged) variable?
Hello!
I have a data set:
set.seed(123)
y<-data.frame(week=seq(as.Date("2010-01-03"), as.Date("2011-01-31"),by="week"))
y$var1<-c(1,2,3,round(rnorm(54),1))
y$var2<-c(10,20,30,round(rnorm(54),1))
# All I need is to create lagged variables for var1 and var2. I looked
around a bit and found several ways of doing it. They all seem quite
complicated - while in
2005 Apr 26
1
Time alignment of time series
One thing that has given me trouble is the fact that the time series
implementation in the class ts relies on the concept of a "start" to
the time series. For example, if I have
ts1 <- ts(c(1,2,3))
dts1 <- diff(ts1)
then dts1 will be a vector c(1,1) but with the attribute start = 2.
Similarly, when one takes lags the "start" is moved around and the
underlying vector