Graphics Reference
In-Depth Information
summary(model)
Call:
lm(formula
=
heightIn ~ ageYear, data
=
heightweight)
Residuals:
Min
1
Q Median
3
Q Max
-8.3517 -1.9006 0.1378 1.9071 8.3371
Coefficients:
Estimate Std. Error t value Pr(
>|
t
|
)
(Intercept)
37.4356
1.8281
20.48
<
2
e
-
16
***
ageYear
1.7483
0.1329
13.15
<
2
e
-
16
***
---
Signif. codes:
0
'
***
'
0.001
'
**
'
0.01
'
*
'
0.05
'
.
'
0.1
' '
1
Residual standard error:
2.989
on
234
degrees of freedom
Multiple R
-
squared:
0.4249
, Adjusted R
-
squared:
0.4225
F
-
statistic:
172.9
on
1
and
234
DF, p
-
value:
<
2.2
e
-
16
This shows that the r
2
value is 0.4249. We'll create a graph and manually add the text using
an-
notate()
(
Figure 5-26
):
# First generate prediction data
pred
<-
predictvals(model,
"ageYear"
,
"heightIn"
)
sp
<-
ggplot(heightweight, aes(x
=
ageYear, y
=
heightIn))
+
geom_point()
+
geom_line(data
=
pred)
sp
+
annotate(
"text"
, label
=
"r^2=0.42"
, x
=
16.5
, y
=
52
)
