diff --git a/survey/survey.tex b/survey/survey.tex
index e713903..0b2ab0b 100644
--- a/survey/survey.tex
+++ b/survey/survey.tex
@@ -775,6 +775,11 @@ We can express bayes theorem thus
 %
 
 
+NOW also we need the justification of using MTTF 
+in probablistic equations.
+
+This is a lambda -exp pow integral....
+
 
 
 RESTRICTIONS: