. 2020 Mar 24;17(6):2153. doi: 10.3390/ijerph17062153

Table 2.

Drilling time measurements.

Operator	N	Mean (s)	Standard Deviation	Standard Error	Mean Confidence Interval 95%		Min (s)	Max (s)
Operator	N	Mean (s)	Standard Deviation	Standard Error	Lower Limit	Upper Limit	Min (s)	Max (s)
1	28	43.35 ^a	14.75	2.78	37.63	49.07	24.00	83.69
2	28	51.50 ^ab	19.35	3.65	44.00	59.01	28.18	96.14
3	28	62.47 ^b	16.97	3.20	55.89	69.05	28.74	95.24
4	28	58.32 ^b	24.05	4.54	49.88	68.53	32.15	125.00
Tot	112	54.13	20.24	1.91	50.34	57.92	24.00	125.00

N: number of implant site preparations; Mean (s): mean drilling time expressed in seconds; Min (s): minimum drilling time expressed in seconds; Max (s): maximum drilling time expressed in seconds. Letters a, b and ab indicate statistically significant difference or equality.