Question

A company wants to determine if the average shearing strength of all rivets manufactured is more than 1000 lbs. A sample of 25 rivets is selected and tested for the shearing strength. After calculation, the mean shearing strength of these 20 selected rivets is 1003.8 lbs and a 99% confidence interval is (1001.4, 1006.2) for the average shearing strength of all rivets manufactured. Which of the following statement is true?

A- The average shearing strength of all rivets manufactured is1003.8lbs.
B- The average shearing strength of all rivets manufactured must be between 1001.4 and1006.2.
C- We are 99% confident that the average shearing strength of all rivets manufactured is more than 1000 lbs.
D- At 90% confidence level, we know that the average shearing strength of all rivets manufactured is between 1001.4 and 1006.2 lbs.

Answer 1

B- The average shearing strength of all rivets manufactured must be between 1001.4 and 1006.2.

Step-by-step explanation:

The company manufactures rivets and it want to analyze the strength of the rivets manufactured. For this purpose the company has carried out hypothesis testing in which the confidence interval resulted to be 1001.4, 1006.2, this indicates that the average strength of each rivet must be between the two values.