how is mttr calculated

5:39

11:17

12:42

1:10

17:29

8:19

7:00

12:18

3:20

1:19

6:43

2:26

1:15

18:16

4:58

7:56

7:10

13:17

11:17

10:55

2:46

7:57

9:50

2:37

14:49

3:25

3:20

2:45

5:02

20:47

10:02

4:52

7:21

2:47

1:21

4:00

10:05

32:16

14:01

2:43