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Table 4 Mean differences (MD= Vent1 – Vent2) between the ventilators with the results of the post hoc contrasts with Bonferroni correction (df = 47), the post hoc t tests without corrections, and the effect sizes (Cohen’s d)

From: The usability of ventilators: a comparative evaluation of use safety and user experience

  Contrasts with Bonferroni correction Post hoc t tests without correction Effect size
MD (Mvent1 Mvent2) p t(47) p Cohen’s d
Use error/close calls (%) Use safety
Vent1 Vent2      
G5 PB980 −0.391 1.000 −0.209 0.835 0.03
G5 SERVO-U 3.646 0.044a 2.804 0.007a 0.40
G5 V500 −4.167 0.292 −2.024 0.049a 0.29
PB980 SERVO-U 4.036 0.149 2.319 0.025a 0.33
PB980 V500 −3.776 0.287 −2.032 0.048a 0.29
SERVO-U V500 −7.813 0.002a −3.824 <0.001a 0.55
NASA-TLX (0–100) Workload
Vent1 Vent2      
G5 PB980 −15.449 < 0.001a −4.404 < 0.001a 0.64
G5 SERVO-U 6.765 0.153 2.308 0.025a 0.33
G5 V500 −6.379 0.547 −1.725 0.091 0.25
PB980 SERVO-U 22.214 < 0.001a 7.524 < 0.001a 1.09
PB980 V500 9.070 0.072 2.615 0.012 0.38
SERVO-U V500 −13.144 < 0.001a −4.323 < 0.001a 0.62
PSSUQ (1–7) System usability
Vent1 Vent2      
G5 PB980 −0.807 0.035a −2.884 0.006 0.42
G5 SERVO-U 0.935 < 0.001a 4.363 < 0.001a 0.63
G5 V500 −0.452 0.508 −1.761 0.085 0.25
PB980 SERVO-U 1.742 < 0.001a 7.456 < 0.001a 1.07
PB980 V500 0.354 1.000 1.195 0.238 0.17
SERVO-U V500 −1.388 < 0.001a −6.221 < 0.001a 0.87
  1. Negative M D values representing Vent1 performing better than Vent2
  2. aStatistically significant results