  Zero factorial, defined to be one, is often counterintuitive to students but
nonetheless an interesting concept to convey in a classroom environment. The
challenge is to delineate the concept in a simple and effective way through the
practice of justification, a familiar concept in mathematics and science
education. In this regard two algebraic and one statistical justification using
the squeeze theorem are presented. To assess the effectiveness of the
justifications, a student survey was conducted at a comprehensive university
incorporating the analysis of the pre- and post-presentation statements. They
clearly present that the justifications are useful in giving credence to zero
factorial equals one. Overall, the results from the online survey supports that
the students preferred Justification 1. The justifications provide instructors
alternative ways to initiate exploration of students' intuitive set up of
comprehending unobvious facts like zero factorial equals one.
  For a range of learners with their varied abilities to perform various mental
activities most closely associated with learning and problem-solving, the
justifications as simple alternative methods offer the potential to raise the
current level of cognitive skills to inspire differentiated paths of learning.
These are evident from survey results noting the role of statistical thinking
and techniques.
