AddHealth | R Documentation |
This data was taken from the National Longitudinal Study of Adolescent Health. It is a cross-sectional sample of participants from grades 7–12, described and analyzed by Warne (2014).
A data frame with 4344 observations on the following 3 variables.
grade
an ordered factor with levels 7
<
8
< 9
< 10
< 11
< 12
depression
a numeric vector
anxiety
a numeric vector
depression
is the response to the question "In the last month, how
often did you feel depressed or blue?"
anxiety
is the response to the question "In the last month, how often
did you have trouble relaxing?"
The responses for depression
and anxiety
were recorded on a
5-point Likert scale, with categories 0="Never", 1="Rarely",
2="Occasionally", 3="Often", 4="Every day"
Warne, R. T. (2014). A primer on Multivariate Analysis of Variance (MANOVA) for Behavioral Scientists. Practical Assessment, Research & Evaluation, 19 (1). https://scholarworks.umass.edu/pare/vol19/iss1/17/
data(AddHealth)
if(require(dplyr) & require(ggplot2)) {
# find means & std.errors by grade
means <- AddHealth |>
group_by(grade) |>
summarise(
n = n(),
dep_se = sd(depression, na.rm = TRUE) / sqrt(n),
anx_se = sd(anxiety, na.rm = TRUE) / sqrt(n),
depression = mean(depression),
anxiety = mean(anxiety) ) |>
relocate(depression, anxiety, .after = grade) |>
print()
# plot means with std.error bars
ggplot(data = means, aes(x = anxiety, y = depression,
color = grade)) +
geom_point(size = 3) +
geom_errorbarh(aes(xmin = anxiety - anx_se,
xmax = anxiety + anx_se)) +
geom_errorbar(aes(ymin = depression - dep_se,
ymax = depression + dep_se)) +
geom_line(aes(group = 1), linewidth = 1.5) +
geom_label(aes(label = grade),
nudge_x = -0.015, nudge_y = 0.02) +
scale_color_discrete(guide = "none") +
theme_bw(base_size = 15)
}
# fit mlm
AH.mod <- lm(cbind(anxiety, depression) ~ grade, data=AddHealth)
car::Anova(AH.mod)
summary(car::Anova(AH.mod))
heplot(AH.mod, hypotheses="grade.L",
fill=c(TRUE, FALSE),
level = 0.4)
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