datarium (version 0.2.0)

depression: Depression Data for Two Way Mixed ANOVA

Description

The data correspond to an experiment in which a treatment for depression is studied. Two groups of patients - control ("ctr") and treatment ("treated") - have been followed at four different time points: t0 (pre-test) and three post-test follow-up measurements (t1, t2, t3). The dependent variable is a depression score.

Repeated measures ANOVA can be performed in order to determine the effect of the treatment and the effect of time on the depression score.

For a worked tutorial on this analysis, see the Datanovia lesson “Mixed ANOVA in R: One Between- and One Within-Subjects Factor” (https://www.datanovia.com/learn/biostatistics/anova/mixed-anova-in-r).

Usage

data("depression")

Format

A data frame with 24 rows and 6 columns (stored as a tibble).

id

participant identifier (1 to 24).

treatment

the treatment group, "ctr" (control) or "treated".

t0

the depression score at pre-test.

t1

the depression score at the first post-test follow-up.

t2

the depression score at the second post-test follow-up.

t3

the depression score at the third post-test follow-up.

The depression score is a simulated measure on an arbitrary scale with no real-world units.

See Also

Datanovia tutorial: Mixed ANOVA in R: One Between- and One Within-Subjects Factor.

Examples

data(depression)
head(depression)

# Two-way mixed ANOVA: treatment (between) x time (within)
depression_long <- reshape(depression, varying = c("t0", "t1", "t2", "t3"),
                           v.names = "score", timevar = "time",
                           direction = "long")
summary(aov(score ~ treatment * factor(time) + Error(factor(id)/factor(time)),
            data = depression_long))