diff --git a/coursera_compneuro/w3quiz/quiz3.py b/coursera_compneuro/w3quiz/quiz3.py
new file mode 100644
index 0000000..95c0910
--- /dev/null
+++ b/coursera_compneuro/w3quiz/quiz3.py
@@ -0,0 +1,29 @@
+# %%
+
+import numpy as np
+from scipy.stats import norm
+import pandas as pd
+
+
+x = np.linspace(0, 10, 100)
+y = []
+
+for i, (loc, sd) in enumerate([(5,.5),(7,1)]):
+  cost = 2 if i == 0 else 1
+  y.append(norm.pdf(x,loc,sd) * cost)
+
+
+df = pd.DataFrame({'x': x})
+df[['s0','s1']] = np.array(y).T
+df = df.melt(id_vars='x',value_name='pdf',var_name='stimulus')
+
+
+import matplotlib.pyplot as plt
+import seaborn as sns
+
+sns.lineplot(data=df,x='x',y='pdf',hue='stimulus')
+
+plt.vlines([5.978,5.667,5.830,2.69],
+           ymin=0,ymax=1.6,
+           colors=['r','g','b','y'],
+           lw=1, linestyles='--')