Statistical analysis
All data analyses were done using the program R version 4.0.2. All data
were examined and found to be non-parametric by Shapiro-Wilk’s test,
visual evaluation of QQ plots and density plots. Descriptive analysis,
along with quantile sets, were calculated and box plots were created to
describe and visualize the data. The non-parametric Kruskal-Wallis test
and Games-Howell post hoc test were used to examine statistically
significant differences between the ordinal test groups for continuous
outcome variables (BAL cytology and BAL volume instilled and aspirated).
Associations between ordinal variables TMS, clinical signs, asthma
types, housing factors and age groups were assessed by Chi-square tests
of independence. All p values were assessed at a significance level of
5%.