Question 26 3 pts A design engineer wants to construct a mean chart for controlling the service life of a halogen headlamp his company produces. He tested service life on randomly picked three samples with four headlamps each, with these results: sample 1 2 3 4 5 1 800 900 1000 900 800 2 900 700 900 900 800 3 800 900 900 1000 1000 4 900 900 900 900 900 What is the estimate of the process mean for whenever it is under control? 885 840 O 850 900