TY  - JOUR
T1  - ISchemic injury and necrotizing tracheobronchitis
AU  - WISWELL TE
Y1  - 1989/11/01
N1  - 10.1001/archpedi.1989.02150230017005
JO  - American Journal of Diseases of Children
SP  - 1259
EP  - 1260
VL  - 143
IS  - 11
N2  - Sir.—The article by Hanson et all in the October 1988 issue of AJDC somewhat supported a personal belief that ischemic injury is involved in the propagation of necrotizing tracheobronchitis (NTB). However, I do not believe that their data justify a causal relationship, as the title of the article would imply. Although 58 infants with NTB had either profound hypotension or low 5-minute Apgar scores (the "ischemia" factors that differentiated them from the controls), the remaining 64 affected infants (54%) had neither of these factors. Furthermore, the authors state that their data were analyzed with "a two-tailed t test."1 I suspect that they actually meant that X2 analysis was used. Simplistically, the t distribution is a method of com= paring two group means, while the X2 statistic compares rates or frequencies of discrete findings. The P values presented in the tables are actually those that one would
SN  - 0002-922X
M3  - doi: 10.1001/archpedi.1989.02150230017005
UR  - http://dx.doi.org/10.1001/archpedi.1989.02150230017005
ER  -