diff --git a/education/statistics/Sampling.md b/education/statistics/Sampling.md
index 2078c21..823b6cc 100644
--- a/education/statistics/Sampling.md
+++ b/education/statistics/Sampling.md
@@ -72,7 +72,9 @@ Remember that the *parameter* is the *number* that actually describes the popula
 
 For any unknown average, the probability histogram of the sample averages will be shaped like the normal curve and centered at the true average with a standard deviation equal to $SE_{ave}$. 
 
-$$ sample_{ave} \pm 2 * se_{ave} $$
+$$ sample_{ave} \pm 2 * SE_{ave} $$
+This equation should be a review:
+$$ SE_{ave} = \frac{SD}{\sqrt{size\space samp}} $$
 The above equation will give you an interval that you can be 95% confident that the true random will be within that point.
 
-95% does *not* mean that 95% of the data is in the interval, it just means we are 95% confident that the actual point is going to lie within the range specified. 
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+95% does *not* mean that 95% of the data is in the interval, it just means we are 95% confident that the actual point is going to lie within the range specified.
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