(Choose 1 answer)
(See picture)
Α. (74.42. 74.64)
Β. (74.44, 74.62)
C. (74.38.74.68)
D. (74.40, 74.66)
A manufacturer produces piston rings for an automobile engine. It is known that ring diameter is normally distributed with σ = 0.25 millimeters. A random sample of 15 rings has a mean diameter of 74.53 millimeters. Find a 95% two-sided confidence interval on the true mean diameter.
Let Z0.025 1.960; 20.05 1.645.
an tot ni
Exit 37
