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python-3.xmatplotlibseaborn

Is there a way to plot 2x Standard Deviation in Seaborn?

For Seaborn lineplot, it seems pretty easy to plot the Standard Deviation by specifying ci='sd'. Is there a way to plot 2 times the standard deviation?

For example, I have a graph like this:

enter image description here

sns.lineplot(data=df, ax=x, x='day_of_week', y='y_variable', color='lightgrey', ci='sd')

Is there a way to make it so the "CI" plotted is 2 times the standard deviation?

Solution

  • I didn't find a solution within the seaborn, but a walk-around way is by using matplotlib.pyplot.fill_between, as, e.g., was done in this answer, but also in the thread suggested in the comments.

    Here is my implementation:

    import matplotlib.pyplot as plt
import seaborn as sns

sns.set_theme()

flights = sns.load_dataset("flights")
fig, axs = plt.subplots(1, 2, figsize=(12, 6), sharey=True)
sns.lineplot(data=flights, x="year", y = "passengers", ci="sd", ax=axs[0])
axs[0].set_title("seaborn")

means = flights.groupby("year")["passengers"].mean()
stds = flights.groupby("year")["passengers"].std()
axs[1].plot(means.index, means.values)
for nstd in range(1, 4):
    axs[1].fill_between(means.index, (means - nstd*stds).values, (means + nstd*stds).values, alpha=0.3, label="nstd={}".format(nstd))
axs[1].legend(loc="upper left")
axs[0].set_title("homemade")
plt.savefig("./tmp/flights.png")
plt.close(fig)

    The resulting figure is enter image description here