2.5 Statistical analysis
R version 3.5.3 was used for statistical analysis. P < 0.05
indicated statistical signif-icance. Measurement data are expressed as
mean ± standard deviation (x ± s) and counti-ng data as rate (%). The
correct recognition rate of odors in each test was calculated, and the
test scores in the modification process were tested by paired sample
Friedman M test. The correct recognition rate of odors in the SSOI and
CMOI tests was tested by the paire-d sample Wilcoxon signed rank-sum
test. Draw FIGURE 1 and FIGURE 2 with GraphP-ad Prism 8 (GraphPad
Software, La Jolla, CA, USA).