## In a manufacturing process a random sample of 9 bolts manufactured has a mean length of 3 inches with a standard deviation of .3 inches. Wha

Question

In a manufacturing process a random sample of 9 bolts manufactured has a mean length of 3 inches with a standard deviation of .3 inches. What is the 95% confidence interval for the true mean length of the 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

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2021-11-10T04:55:48+00:00
2021-11-10T04:55:48+00:00 1 Answer
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## Answers ( )

Answer:The correct option is (

C) (2.769, 3.231).Step-by-step explanation:The confidence interval for mean when the standard deviation is not known is:

Given:

Compute the critical value as follows:

**Use a

t-table.The 95% confidence interval for true mean length of the bolt is:

Thus, the 95% confidence interval for true mean length of the bolt is (

2.769, 3.231).The correct option is (

C).