Table 12.3: TABLE 12.2 Thirty control chart subgroups of lab test turnaround times (in minutes)
Subgroup Turnaround observations Subgroup mean Range
1 39 33 65 50 41 45.6 32
2 46 36 34 53 37 41.2 19
3 37 35 28 37 41 35.6 13
4 50 38 35 60 39 44.4 25
5 29 27 22 43 50 34.2 28
6 32 35 40 27 42 35.2 15
7 42 43 37 44 39 41.0 7
8 40 45 50 43 24 40.4 26
9 34 47 54 39 51 45.0 20
10 43 65 25 45 25 40.6 40
11 35 48 44 45 34 41.2 14
12 55 54 44 36 55 48.8 19
13 29 39 47 42 47 40.8 18
14 41 31 29 37 27 33.0 14
15 41 40 32 33 52 39.6 20
16 32 32 41 47 43 39.0 15
17 24 54 34 53 56 44.2 32
18 36 45 53 31 31 39.2 22
19 48 57 36 31 30 40.4 27
20 38 27 39 35 27 33.2 12
21 53 33 51 50 42 45.8 20
22 53 45 37 44 33 42.4 20
23 27 50 35 29 47 37.6 23
24 39 39 51 49 44 44.4 12
25 33 29 38 68 34 40.4 39
26 34 43 48 49 56 46.0 22
27 43 20 51 49 50 42.6 31
28 33 42 51 58 26 42.0 32
29 25 46 25 43 42 36.2 21
30 30 34 42 36 51 38.6 21