Displaying 20 results from an estimated 10000 matches similar to: "t-test problem"
2010 Aug 30
3
Putting legend *outside* plotting area
Is there a simple way to put a legend outside the plot area for a simple
plot?
I found... (at http://www.harding.edu/fmccown/R/)
# Expand right side of clipping rect to make room for the legend
*par(xpd=T, mar=par()$mar+c(0,0,0,4))*
# Graph autos (transposing the matrix) using heat colors,
# put 10% of the space between each bar, and make labels
# smaller with horizontal y-axis labels
2011 Nov 11
3
Why does length("") == 1?
It seems obvious to me that the empty string "" is length 0.
cheers
Worik
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2009 Sep 24
2
Date formats in as.Date
I have trouble with this:
as.Date("Sep-1981", format="%b-%Y")
Returns "NA"
>From documentation for strftime
'%b' Abbreviated month name in the current locale. (Also matches
full name on input.)
'%Y' Year with century.
What am I doing wrong?
cheers
Worik
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2012 Oct 09
4
Modern Symbolic debugger for R programmes?
I think I am whistling in the wind, but is there a modern symbolic
debugger for R programmes?
I am working through some one else's code, thousands of lines, that
has the occasional bug in it, and a lot in my understanding of it.
I cannot make setBreakpoint or findLineNum work. I get "No source
refs found.". I am starting to loose my mind!
A debugger where I could set
2012 Apr 19
2
Trouble with [sv]apply
Friends
I clearly donot understand how sapply and vapply work.
What I have is a function that returns a matrix with an indeterminate
number of rows (some times zero) but a constant number of columns. I
cannot reliably use an apply function to assemble the matrices into a
matrix. I am not sure it is possible.
I can demonstrate the core of my confusion with this simple code.
A.f <-
2010 Jun 13
2
Scope and sapply
I am puzzled by the scope rules that apply with sapply.
If I want to modify a vector with sapply I tried...
N <- 10
vec <- vector(mode="numeric", length=N)
test <- function(i){
vec[i] <- i
}
sapply(1:N, test)
vec
but it not work.
How can this be done?
Worik
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2008 Apr 03
3
summary(object, test=c("Roy", "Wilks", "Pillai", ....) AND ellipse(object, center=....)
Dear All,
I would be very appreciative of your help with the following
1). I am running multivariate multiple regression through the manova() function (kindly suggested by Professor Venables) and getting two different answers for test=c("Wilks","Roy","Pillai") and tests=c("Wilks","Roy",'"Pillai") as shown below. In the
2008 Oct 15
2
dynlm and lm: should they give same estimates?
Hi,
I was wondering why the results from lm and dynlm are not the same for what I think is the same model.
I have just modified example 4.2 from the Pfaff book, please see below for the code and results.
Can anyone tell my what I am doing wrongly?
Many thanks,
Werner
set.seed(123456)
e1 <- rnorm(100)
e2 <- rnorm(100)
y1 <- ts(cumsum(e1))
y2 <- ts(0.6*y1 + e2)
lr.reg <- lm(y2
2005 May 04
3
Multivariate multiple regression
I'd like to model the relationship between m responses Y1, ..., Ym and a
single set of predictor variables X1, ..., Xr. Each response is assumed
to follow its own regression model, and the error terms in each model
can be correlated. My understanding is that although lm() handles
vector Y's on the left-hand side of the model formula, it really just
fits m separate lm models. What should
2009 Aug 30
2
correlation between two 2D point patterns?
Suppose I have two sets of (x,y) points like this:
x1<-runif(n=10)
y1<-runif(n=10)
A<-cbind(x1,y1)
x2<-runif(n=10)
y2<-runif(n=10)
B<-cbind(x2,y2)
I would like to measure how similar the two sets of points are.
Something like a correlation coefficient, where 0 means the two
patterns are unrelated, and 1 means they are identical. And in
addition I'd like to be able to
2012 Mar 16
1
multivariate regression and lm()
Hello,
I would like to perform a multivariate regression analysis to model the
relationship between m responses Y1, ... Ym and a single set of predictor
variables X1, ..., Xr. Each response is assumed to follow its own
regression model, and the error terms in each model can be correlated.
Based on my readings of the R help archives and R documentation, the
function lm() should be able to
2008 Feb 18
3
mean and variance of ratio
Hi all!
I try to estimate a statistic of the form: (x1-x2)/(y1-y2), where
x1,x2,y1,y2 represent variable means, so each has an estimate and
standard error associated with it.
How is it possible to estimate the mean and the variance of this ratio?
Thank you!
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2008 Jun 04
1
Comparing two regression lines
Dear R users,
Suppose I have two different response variables y1, y2 that I regress separately on the same
explanatory variable, x; sample sizes are n1=n2.
Is it legitimate to compare the regression slopes (equal variances assumed) by using
lm(y~x*FACTOR),
where FACTOR gets "y1" if y1 is the response, and "y2" if y2 is the response?
The problem I see here is that the
2012 Nov 30
3
Line numbers with errors and warnings?
Is it possible to get a line number with an error report?
I have a long script and an error:
Error in `[.xts`(x, xsubset) : subscript out of bounds
It would be very helpful, and save a lot of time, if there was some
indication in the error message which line the error was.
I can find it using binary search but that is a painful process.
cheers
Worik
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2011 May 08
2
Pretty printing numbers
Friends
I am trying to format a number to a string so 2189.745 goes to "2,189.35"
and 309283.929 goes to "309,283.93"
I have tried to use formatC(X, big.mark=",",drop0trailing=FALSE, format="f")
but it does not get the number of decimals correct. Specifying digits does
not work as that is significant digits. I could use a switch statement
switching on
2011 Sep 13
1
Getting Rcpp SEXP data in C++
Friends
I am looking at Rcpp and I am a bit stuck on a simple matter.
(I am calling R from c++, if there is a better way...)
Given this simple example using the TTR package and the SMA function which
returns a simple moving average....
Rcpp::NumericVector rv;
for(int i = 0; i < 100; i++){
rv.push_back(rand());
}
Rcpp::Environment TTR("package:TTR");
2010 Mar 18
1
Locating an error
I have a large programme that after running half an hour or so fails with an
error
Error in x[value] <- NA : only 0's may be mixed with negative subscripts
How can I find out where that error occurs?
If I have to do a binary search using error messages it will take a long
time! Is there some way I can generate a stack trace?
cheers
Worik
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2008 Apr 23
2
Incrementing Dates
How can I increment the value of a Date class?
I want to add a day, month or year to a date.
cheers
Worik
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2012 Mar 25
2
Weird POSIXct behaviour
Friends
I have an xts that I wish to access.
Browse[2]> DATA.ba[[p]]["2012-03-20 00:59:57","bid"]
bid
2012-03-20 00:59:57 1.4993
So far so good.
Now putting the index into a variable:
Browse[2]> Time
[1] "2012-03-20 00:59:57 NZDT"
Browse[2]> DATA.ba[[p]][Time, "bid"]
bid
Where has it gone?
Looking closer....
2010 Jun 08
2
Logical vector question
If I create a vector thusly
> v1 <- runif(20, min=0, max=1)
> v1
[1] 0.9754443 0.6306228 0.3238158 0.3175769 0.6791534 0.6956507 0.3840803
[8] 0.1421328 0.8592398 0.4388306 0.9472040 0.4727435 0.5645302 0.7391616
[15] 0.6116199 0.2727754 0.2657867 0.5261744 0.8764804 0.2032126
And I want to create a logical vector the same length that is true if v1<.3
or v1 > .7 how do I do it