diff --git a/education/statistics/Hypothesis Tests.md b/education/statistics/Hypothesis Tests.md
index 675ca31..ac6995b 100644
--- a/education/statistics/Hypothesis Tests.md	
+++ b/education/statistics/Hypothesis Tests.md	
@@ -74,6 +74,10 @@ The $\chi^2$ curve does not follow the normal curve. It has a long right hand ta
 
 $$ df = num_{terms} - 1 $$
 
-There will never be a $\chi^2$ statistic.
+%% There will never be a $\chi^2$ statistic. (i don't know what this means but it was in my notes) %%
 
-Ch ($\chi$), i is pronounced khai
\ No newline at end of file
+Ch ($\chi$), i is pronounced khai
+
+Difference between $\chi ^2$ and z-test
+ - The $\chi ^2$-test says whether the data are like the result of drawing at random from a box whose *contents* are given.
+- The z-test says whether the data are like the result of drawing at random from a box whose *average* is given.