Question

I am having problems trying to add the 95% CI (lower/upper) to an existing plot using the values from two columns in a matrix. What would be the best way to use this information to add the error bars?

Here is a sample of my data:

option<-read.table(text="
distance p.move id option   mean lower95%CI upper95%CI
1      close   0.05  1    10% 13.682     11.306     15.768
2      close   0.10  2    10% 10.886      9.336     12.270
3      close   0.15  3    10%  8.402      7.262      9.580
4      close   0.20  4    10%  7.240      6.132      8.350
5      close   0.25  5    10%  6.322      5.288      7.370
6      close   0.30  6    10%  5.850      4.920      6.714
7      close   0.35  7    10%  3.838      3.084      4.648
8      close   0.40  8    10%  3.600      2.936      4.200
9      close   0.45  9    10%  3.380      2.702      4.016
10     close   0.50 10    10%  3.152      2.462      3.720
11     close   0.55 11    10%  2.772      2.214      3.286
12     close   0.60 12    10%  3.072      2.458      3.596
13     close   0.65 13    10%  2.670      2.134      3.212
14     close   0.70 14    10%  2.194      1.724      2.634
15     close   0.75 15    10%  1.980      1.612      2.336
16     close   0.80 16    10%  2.028      1.594      2.466
17     close   0.85 17    10%  1.650      1.294      1.974
18     close   0.90 18    10%  1.916      1.564      2.254",header=T)

option

This is my plot:

plot(option$mean~option$p.move,xlim=c(0,1),type="o",ylim=c(0,20),
xlab="Probability",ylab="% time",col=1,lwd=1.85)

Thanks a lot in advance,

Answer 1

You can just add the extra columns in with lines which is like plot but draws on the existing plot. (see ?lines, ?points).

Also, when you plot with a data frame you can skip all the option$ by feeding option into the dat argument (see ?plot):

# draw original plot
plot(mean ~ p.move, dat=option, xlim=c(0,1), type="o", ylim=c(0,20),
     xlab="Probability",ylab="% time",col=1,lwd=1.85)

# draw extra lines (the '%' in the column names gets converted to '.' by R)
# note you can put your usual `plot` arguments into `lines` like lwd, type etc
# if you want
lines(upper95.CI ~ p.move, option)
lines(lower95.CI ~ p.move, option)