Question
A manufacturer must test that his bolts are 2.00 cm long when they come off the assembly line. He must recalibrate his machines if the bolts are too
long or too short. After sampling 169 randomly selected bolts off the assembly line, he calculates the sample mean to be 2.05 cm . He knows that the
population standard deviation is 0.29 cm . Assuming a level of significance of 0.01 , is there sufficient evidence to show that the manufacturer needs
to recalibrate the machines?
Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below.
A manufacturer must test that his bolts are 2.00 cm long when they come off the assembly line. He must recalibrate his machines if the bolts are too |
long or too short. After sampling 169 randomly selected bolts off the assembly line, he calculates the sample mean to be 2.05 cm . He knows that the |
population standard deviation is 0.29 cm . Assuming a level of significance of 0.01 , is there sufficient evidence to show that the manufacturer needs |
to recalibrate the machines? |
Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. |
|
Ask by Chavez Reeves. in the United States
Dec 24,2024
Upstudy AI Solution
Tutor-Verified Answer
Answer
The hypotheses are:
Solution

Sign in to Unlock Answers for Free!
A Learning Platform Trusted by Millions of Real Students and Teachers.

Answered by UpStudy AI and reviewed by a Professional Tutor
Like
Bonus Knowledge
To test if the manufacturer needs to recalibrate the machines, we set up our hypotheses. The null hypothesis
states that there is no need for recalibration and that the mean length of the bolts is indeed 2.00 cm. In contrast, the alternative hypothesis
suggests that the average length differs from this target, indicating that recalibration is necessary. This can be formally stated as:
This sets the stage for us to conduct a two-tailed test to determine whether the bolts are significantly different from the required length.
Next, when taking samples for testing, it’s essential to ensure randomness. This means selecting bolts in a way that any bolt has an equal chance of being included in the sample. A common mistake is using a non-random sampling method, such as only picking from the first few bolts off the assembly line. This can lead to biased results and give an inaccurate representation of the population, potentially skewing the conclusions drawn from the hypothesis test. Remember, randomness is key!