fig_2 = plt.figure(figsize=(18,6))

sns.regplot(x=pca_vectors[:,209],y=df_y, label='Principal Component 210',x_bins=10)
sns.regplot(x=pca_vectors[:,210],y=df_y, label='Principal Component 211',x_bins=10)
sns.regplot(x=pca_vectors[:,211],y=df_y, label='Principal Component 212',x_bins=10)

plt.title('Least Important Principal Components vs Reference Value')
plt.xlabel('Principal Component Value')
plt.ylabel('Reference Value')
plt.legend()
plt.show()