There is line shadow showing the confidence interval, because the dataset contains multiple y(team_strikerate) values for each x(season) value. By default, sns.lineplot()
will estimate the mean by aggregating over multiple y values at each x value.
After aggregation, the mean of y values at each x value will be plotted as a line. The line shadow represents the confidence interval of the estimate.
To remove the line shadow, you can pass the argument ci=None
to sns.lineplot()
.
(credit to @JohanC for providing this idea in this question’s comment)