Statistical Debugging

Question 1

Increase() measure

Answer 1

Increase(P) = Failure(P) - Context(P)

Question 2

Failure(P)

Answer 2

Failure(P) = F(P) / (F(P) + S(P))

F(P) - # failing runs where P is observed to be true

S(P) - # successful runs where P is observed to be true

Question 3

Context(P)

Answer 3

Context(P) = F(P observed) /(F(P observed) + S(P observed))

Question 4

Abstracting Predicate Counts

Answer 4

• Never observed
  0 False at least once, never true
  1 True at least once, never false
• Both true and false at least once