fix spelling error

Author: drbenvincent

docs/source/notebooks/event_study_pymc.ipynb

@@ -1285,7 +1285,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "We can see that not including time fixed effects means that we are unable to account for time-based shocks that affect all units identically. The consequence of this is that our causal estimates (the dynamic treatment effects) are now biased. This is most noticable with the pre-intervention placebo checks, where we see meaningful deviations from zero effect _before_ the intervention."
+    "We can see that not including time fixed effects means that we are unable to account for time-based shocks that affect all units identically. The consequence of this is that our causal estimates (the dynamic treatment effects) are now biased. This is most noticeable with the pre-intervention placebo checks, where we see meaningful deviations from zero effect _before_ the intervention."
    ]
   },
   {