Hello Everyone, Below is the table each id column contains 7 visits and their value is in AC107c column. I want to use lowess function in R to get a smooth fitted value (one out of 7) for each ID. Please help me how I can do it in R. Thanks!!
VisitID ID AC107c
V5 A 70
V6 A 67
V1 A 75
V8 A 62
V4 A 78
V7 A 74
V3 A 80
V6 B 101
V3 B 109
V4 B 100
V7 B 103
V1 B 94
V8 B 100
V5 B 103
V1 C 81
V8 C 86
V5 C 84
V6 C 83
V4 C 88
V3 C 86
V7 C 85
•
written
by
georgians •
You could try something like this, this example just for ID 'A':
options(scipen = 9)
data
VisitID ID AC107c
4 V8 A 62
2 V6 A 67
1 V5 A 70
6 V7 A 74
3 V1 A 75
5 V4 A 78
7 V3 A 80
15 V1 C 81
18 V6 C 83
17 V5 C 84
21 V7 C 85
16 V8 C 86
20 V3 C 86
19 V4 C 88
12 V1 B 94
10 V4 B 100
13 V8 B 100
8 V6 B 101
11 V7 B 103
14 V5 B 103
9 V3 B 109
data <- data[order(data$AC107c),]
data_A <- data.frame(Visit = 1:7, subset(data, ID == 'A'))
data_A
Visit VisitID ID AC107c
4 1 V8 A 62
2 2 V6 A 67
1 3 V5 A 70
6 4 V7 A 74
3 5 V1 A 75
5 6 V4 A 78
7 7 V3 A 80
loessfit <- loess(Visit ~ AC107c, data = data_A)
plot(data_A$Visit ~ data_A$AC107c, pch = 20, las = 1, xlab = 'AC107c', ylab = 'VisitID')
lines(data_A$AC107c, predict(loessfit), col = "red2", lwd = 2)
# add correlation and p-value
r <- round(cor(data_A$AC107c, data_A$Visit, use = "complete.obs", method = "spearman"), 3)
pval <- cor.test(data_A$AC107c, data_A$Visit, use = "complete.obs", method = "spearman")$p.value
pval <- ifelse(pval < 0.0001, "< 0.0001", format(pval, digits = 2))
text(70, 7, paste("r, ", r, ",\np, ", pval, sep=""), adj=c(0, 1), cex=0.8)
There are not many data-points here; so, it does not look too hot.
Kevin
Thank you so much for your kind help. But my actual problem is I want to predict one value for each id from 7 visits with the help of the LOWESS function. Also if possible, please let me know how to incorporate the loop because I have more than 500 ids data. Thank you!!
Take a look at the predict() function - you will also require the loessfit object
For the loop, I may ask that you have a think about that in your own time.
Thank you so much for your kind suggestions.
Log in to answer this question.
