A survey was given to a group of primigravidas attending a birthing class at their local hospital. The test was given in their first trimester and then again in the third trimester to assess the degree of difference in perceived anxiety levels in primigravidas at the beginning and end of their pregnancy. The instrument that was used to assess anxiety ranked responses on a scale from 1- 10 (low' to 'very high' levels of anxiety). Which would be the most appropriate statistical test to analyze these data