In a manufacturing process a random sample of 36 bolts manufactured has a mean length of 3cm with a standard deviation of 0.3cm.Assuming bolt length is normally distributed,what is the 99% confidence interval for the true mean length of the bolt?
A)2.902 to 3.098
B)2.884 to 3.117
C)2.864 to 3.136
D)2.228 to 3.772
E)2.902 to 3.772

Question

Quizplus · Accepted Answer

The 99% confidence interval is calculated using the formula: mean ± (z * (standard deviation/sqrt(n))). For 99% confidence, z is approximately 2.576. Thus, the interval is 3 ± (2.576 * (0.3/√36)) = 2.864 to 3.136.

In a Manufacturing Process a Random Sample of 36 Bolts