In a Manufacturing Process a Random Sample of 9 Manufactured

Multiple Choice

In a manufacturing process a random sample of 9 manufactured bolts has a mean length of 3 inches with a standard deviation of .3 inches and is normally distributed. What is the 95 percent confidence interval for the true mean length of the manufactured bolt?

A) 2.804 to 3.196
B) 2.308 to 3.692
C) 2.769 to 3.231
D) 2.412 to 3.588
E) 2.814 to 3.186