Answer:
D = -7
Step-by-step explanation:
http://goblues.org/faculty/grantm/files/2015/12/Practice-Test-3.7-Solutions.pdf
I think it's question number three. Sorry if the link dosen't work.
Just do what is says to do i can answer it for u but im not sure if it will be correct
i have did this problem before tho
360/12 = 30deg...so the arguments are multiples of 30deg.
71
62
88
38
89
76
-15 (i'm inversing everything to make it simple)
The mean is -69.28
