FR

Spaghetti plot

ggplot(data, aes(x=TIME, y=DV, group=ID)) +
geom_line() +
labs(title="Concentration vs Time",
x="Time (h)",
y="Concentrations (ug/L)")+
geom_hline(yintercept=1.5,
size=2,
color="blue",
linetype="dashed")

img