5. Statistical analysis A descriptive analysis will be made of all the variables, including the demographic data, predictors of difficult intubation, number of insertion and intubation attempts, and the TTK intubation and withdrawal times. Continuous variables will be reported as the mean and standard error, while categorical variables will be reported as frequency and percentage. The chi-squared test will be used to compare categorical variables, while quantitative variables will be contrasted using the Student t-test. The data will be analyzed using the Statistical Package for the Social Sciences (SPSS, Chicago, IL, USA), version 20.0.