MATH 221 Statistics for Decision Making Week 5 Homework
Question 1 From a random sample of 58 businesses, it is found that the mean time the owner spends on administrative issues each week is 21.69 with a population standard deviation of 3.23. What is the 95% confidence interval for the amount of time spent on administrative issues?
Question 2If a confidence interval is given from 43.83 up to 61.97 and the mean is known to be 52.90, what is the margin of error?
Question 3If a computer manufacturer needed a supplier that could produce parts that were very precise, what characteristics would be better?
wide confidence interval with high confidence level
narrow confidence interval at high confidence level
narrow confidence interval at low confidence level
wide confidence interval with low confidence level
Question 4Which of the following are most likely to lead to a wide confidence interval?
large sample size
small standard deviation
large standard deviation
Question 5If you were designing a study that would benefit from a narrow range of data points, you would want the input variable to have:
a small mean
a small sample size
a large standard deviation
a small margin of error
Question 6The 95% confidence interval for these parts is 56.98 to 57.05 under normal operations. A systematic sample is taken from the manufacturing line to determine if the production process is still within acceptable levels. The mean of the sample is 57.06. What should be done about the production line?
Keep the line operating as it is outside the confidence interval
Stop the line as it is close to the confidence interval
Keep the line operating as it is close to the confidence interval
Stop the line as it is outside the confidence interval
Question 7In a sample of 41 temperature readings taken from the freezer of a restaurant, the mean is 29.7 degrees and the population standard deviation is 2.7 degrees. What would be the 80% confidence interval for the temperatures in the freezer?
Question 8What is the 99% confidence interval for a sample of 52 seat belts that have a mean length of 85.6 inches long and a population standard deviation of 2.9 inches?
Question 9If two samples A and B had the same mean and sample size, but sample A had a larger standard deviation, which sample would have the wider 95% confidence interval?
Sample A as it has the larger sample
Sample B as it has the smaller sample
Sample B as its sample is more disperse
Sample A as its sample is more disperse
Question 10Why might a company use a lower confidence interval, such as 80%, rather than a high confidence interval, such as 99%?
It is cheaper as the sample size needs to be larger
It is faster as the sample size can be smaller
It is faster as more samples can be collected in a shorter time
It is cheaper as more samples can be collected
APA Writing Checklist
Use this document as a checklist for each paper you will write throughout your GCU graduate
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