Table 5 Comparison of mean number of cells with micronucleus between the two groups

From: Genotoxic effects of X-rays in buccal mucosal cells in children subjected to dental radiographs

Cells Group Mean s.d. s.e. of mean Mean difference Z P-Value
Pre-exposure Group 1 2.80 0.70 0.16 −1.400 −4.391 <0.001a
  Group 2 4.20 0.77 0.17    
Postexposure Group 1 6.05 1.10 0.25 −2.100 −4.840 <0.001a
  Group 2 8.15 0.81 0.18    
  1. Before exposure, a higher mean number of cells with micronucleus was recorded in group 2 compared with group 1, and the difference between them was statistically significant (P<0.001).
  2. aSignificant difference.