[R] two questions about xyplot

[William Shadish]

Dear R helpers,

I am generating three artificial short interrupted time series datasets
(single-case designs; call them Case 1, Case 2, Case 3) and then plotting
them in xyplot. I will put the entire code below so you can reproduce. I
have been unable to figure out how to do two things.

1. Each time series has 24 time points divided into four phases. Call them
phases A, B, C, D for convenience. I have used running() to compute the
means of the observations in each of these four parts; and I saved these as
objects called mn1 (for Case 1), mn2 (Case 2) and mn3 (Case 3). So mn1
contains the four means for A, B, C, D phases for Case 1, etc. I want to
insert these means into the xyplot in the appropriate place. For instance,
insert the first mean from mn1 into phase A of Case 1, the second mean into
phase B of Case 1, and so forth until insert the fourth mean from mn3 into
phase D of Case 3. Ideally, it would insert something like "M = 49.02" or
"Xbar = 49.02" into phase A for Case 1.

2. The xyplot code I use creates a line connecting the data points, and that
line is continuous over the entire graph. I would like to have the lines be
discontinuous between phases. Phase changes are indicated by panel.abline()
in the code, and occur at time points 6.5, 12.5, and 18.5. So, for example,
I would like a line connecting the datapoints from 1 to 6, then 7-12, then
13-18, then 19-24 (but not including 6-7, 12-13, and 18-19).

I appreciate any help you might be able to offer.

Will Shadish

Here is the code:
#############################################################################
library(gtools)
library(lattice)
###g = .66
z <- rnorm(24, mean = 0, sd = 10)
w <- rnorm(24, mean = 0, sd = 10)
###change mean = to vary the effect size
tm <- rnorm(6, mean = 10, sd = 10)
b <- rep(0,6)
c <- rep(1,6)
tmt <- c(b,tm,b,tm)
for (t in 2:24) z[t] <- 0.25 * z[t - 1] + w[t]
dvy <- 50 + z + tmt
jid <- rep(1,24)
sid <- rep(1,24)
pid <- rep(1,24)
dvid <- rep(1,24)
desvar <- rep(1,24)
dvdir <- rep(0,24)
sessidx <- c(1:24)
m <- rep(1,6)
n <- rep(2,6)
o <- rep(3,6)
p <- rep(4,6)
numph <- c(m,n,o,p)
phasebtm <- c(b,c,b,c)
d1 <- cbind(jid,sid,pid,dvid,desvar,dvdir,dvy,sessidx,numph,phasebtm)
mn1 <- running(dvy, width=6, by=6)

#second dataset
z <- rnorm(24, mean = 0, sd = 10)
w <- rnorm(24, mean = 0, sd = 10)
tm <- rnorm(6, mean = 10, sd = 10)
b <- rep(0,6)
c <- rep(1,6)
tmt <- c(b,tm,b,tm)
for (t in 2:24) z[t] <- 0.25 * z[t - 1] + w[t]
dvy <- 50 + z + tmt
jid <- rep(1,24)
sid <- rep(1,24)
pid <- rep(2,24)
dvid <- rep(1,24)
desvar <- rep(1,24)
dvdir <- rep(0,24)
sessidx <- c(1:24)
m <- rep(1,6)
n <- rep(2,6)
o <- rep(3,6)
p <- rep(4,6)
numph <- c(m,n,o,p)
phasebtm <- c(b,c,b,c)
d2 <- cbind(jid,sid,pid,dvid,desvar,dvdir,dvy,sessidx,numph,phasebtm)
mn2 <- running(dvy, width=6, by=6)

#third dataset
z <- rnorm(24, mean = 0, sd = 10)
w <- rnorm(24, mean = 0, sd = 10)
tm <- rnorm(6, mean = 10, sd = 10)
b <- rep(0,6)
c <- rep(1,6)
tmt <- c(b,tm,b,tm)
for (t in 2:24) z[t] <- 0.25 * z[t - 1] + w[t]
dvy <- 50 + z + tmt
jid <- rep(1,24)
sid <- rep(1,24)
pid <- rep(3,24)
dvid <- rep(1,24)
desvar <- rep(1,24)
dvdir <- rep(0,24)
sessidx <- c(1:24)
m <- rep(1,6)
n <- rep(2,6)
o <- rep(3,6)
p <- rep(4,6)
numph <- c(m,n,o,p)
phasebtm <- c(b,c,b,c)
d3 <- cbind(jid,sid,pid,dvid,desvar,dvdir,dvy,sessidx,numph,phasebtm)
mn3 <- running(dvy, width=6, by=6)

#concatenate d1 d2 d3
d66 <- rbind(d1, d2, d3)
d66df <- as.data.frame(d66)
d66df$case <- ordered(d66df$pid,
levels = c(1,2,3),
labels = c("Case 3", "Case 2", "Case 1"))
p<-xyplot(dvy ~ sessidx | case, data=d66df,
     layout=c(1, 3), xlab= "Sessions",
     ylab = "Number of Seconds",
     type="l")
update(p, panel=function(...){
         panel.xyplot(...)
         panel.abline(v=6.5)
         panel.abline(v=12.5)
         panel.abline(v=18.5)
} )

-- 
William R. Shadish
Distinguished Professor
Founding Faculty

Mailing Address:
William R. Shadish
University of California
School of Social Sciences, Humanities and Arts
5200 North Lake Rd
Merced CA  95343

Physical/Delivery Address:
University of California Merced
ATTN: William Shadish
School of Social Sciences, Humanities and Arts
Facilities Services Building A
5200 North Lake Rd.
Merced, CA 95343

209-228-4372 voice
209-228-4007 fax (communal fax: be sure to include cover sheet)
wshadish at ucmerced.edu
http://faculty.ucmerced.edu/wshadish/index.htm
http://psychology.ucmerced.edu