diff --git a/is/ub8/is8.pdf b/is/ub8/is8.pdf
index 672e213..b952576 100644
--- a/is/ub8/is8.pdf
+++ b/is/ub8/is8.pdf
Binary files differ
diff --git a/is/ub8/is8.tex b/is/ub8/is8.tex
index 7fb53d0..5929687 100644
--- a/is/ub8/is8.tex
+++ b/is/ub8/is8.tex
@@ -84,7 +84,7 @@
             P(\text{large stone})&=\frac{343}{343+357}=0.49\\
             P_A(R=1)&=\sum\limits_Z P(R=1|Z=z,T=A)P(Z=z)\\
             &=0.73\cdot 0.49 + 0.93\cdot 0.51\approx 0.832\\
-            P_B(R=1)&=\sum\limits_Z P(R=1|Z=z,T=A)P(Z=z)\\
+            P_B(R=1)&=\sum\limits_Z P(R=1|Z=z,T=B)P(Z=z)\\
             &=0.69\cdot 0.49 + 0.87\cdot 0.51\approx 0.782
         \end{align*}
         (Formula from the lecture)\\