Overview
For question 2-6, please look over the "descriptive conf level data analysis" attachment which is a step by step process for a similar question. Descriptive Statistics Function - Mean Confidence Level in Excel
For questions 7-12, which is Descriptive Statistics Function - Proportion Confidence Level in Excel
Please look over "bank wait time excel file" with the problem statement and answers.
Question 2
Tires are among the most commonly replaced parts on vehicles. They are not cheap and shopping for them is confusing. When we look for tires, many of us pay attention to the warranty that accompanies them as a way of getting reliable and long-lasting tires - sometimes paying a hefty premium for high performance.
Tire manufacturers test their tires in house. Tires are inflated to the optimal pressure and then the tires spin on specially designed treadmills.
The thread-life warranties are presented in a mileage estimate. If a tire has worn out evenly across the tread well before its estimated mileage limit, it may qualify for replacement.
Of course, the tire manufacturer would like to minimize warranty replacements by making sure that their tires meet the mileage standard. To this end, the production manager of a tire company is testing their mileage warranty of 30,000 miles. To do the test, 60 tires are put through the treadmill test. When the tires are worn down to the 2/32nd thread-wear indicators, the mileage is recorded. You have the result of one such sample in the file Tire_Mileage.xlsxDownload Tire_Mileage.xlsx
Please utilize this scenario for answering Questions 2 through 6.
Based on the sample, what is the lower bound of the 95% confidence interval of the mean mileage for the tires?
NOTE: Enter numerical values with no commas and round your response to 2 digits after the decimal point.
Question 3
Refer to the scenario presented in Question 2.
Based on the sample, what is the upper bound of the 95% confidence interval of the mean mileage for the tires?
NOTE: Enter numerical values with no commas and round your response to 2 digits after the decimal point.
Question 4
Refer to the scenario presented in Question 2.
What is the probability of finding a sample with a mean of less than 30,000 miles?
Group of answer choices
Virtually 0
.0002
0.337
.4167
Question 5
Refer to the scenario presented in Question 2.
What is the required sample size, if the management wants to be within 250 miles of the actual population mean?
Question 6
Refer to the scenario presented in Question 2 and your findings for Questions 2 through 5. For better understanding of tire warranties, please review "How Tire Warranties WorkLinks to an external site.", paying particular attention to the section titled "Mileage warranty (also known as tread life warranty)". Think about this decision from the perspective of the manufacturer making the decision.
a. Based on your analysis, which one of the three choices would you recommend for this type of tire: (1) keeping the warranty mileage at 30,000 miles; (2) increasing the warranty mileage; or (3) decreasing the warranty mileage? If you are recommending increasing or decreasing the warranty mileage, what should the new warranty mileage be? Please explain why you are making this recommendation.
For parts (b) and (c) below, you do not need to do a formal financial analysis. A general discussion of issues (e.g. a high-level cost-benefit analysis) that should be considered in making this decision is fine!
b. Please explain the possible benefits (pros) of your recommendation.
c. Please explain the possible costs (cons) of your recommendation.
Question 7
To assess how women are doing in the workforce, we have gathered data from 120 firms with 100 to 500 employees, and have recorded how many of the top 25 highest paid employees are female. Use the data provided in Top25_Female.xlsx Download Top25_Female.xlsxto answer Questions 7 through 12.
What is the overall proportion of females in the top 25?
NOTE: Enter a numerical value only, and round your response to 4 digits after the decimal point. For example, you would enter the proportion of .34561 (equivalent to 34.561%) as .3456 in the box below; and .34566 (or 34.566%) as .3457. If you do not follow these formatting and rounding rules, you may not receive credit for your answer.
Question 8
Refer to the scenario presented in Question 7. What is the lower bound of the 95% confidence interval for the mean proportion of females in the top 25?
NOTE: Enter a numerical value only, and round your response to 4 digits after the decimal point. For example, you would enter the value of .34561 (equivalent to 34.561%) as .3456 in the box below; and .34566 (or 34.566%) as .3457. If you do not follow these formatting and rounding rules, you may not receive credit for your answer.
Question 9
Refer to the scenario presented in Question 7.
What is the upper bound of the 95% confidence interval for the mean proportion of females in the top 25?
NOTE: Enter a numerical value only, and round your response to 4 digits after the decimal point. For example, you would enter the value of .34561 (equivalent to 34.561%) as .3456 in the box below; and .34566 (or 34.566%) as .3457. If you do not follow these formatting and rounding rules, you may not receive credit for your answer.
Question 10
Refer to the scenario presented in Question 7.
What is the lower bound of the 95% confidence interval for the proportion of firms that have more than 50% female in the top 25 list?
NOTE: Enter a numerical value only, and round your response to 4 digits after the decimal point. For example, you would enter the value of .34561 (equivalent to 34.561%) as .3456 in the box below; and .34566 (or 34.566%) as .3457. If you do not follow these formatting and rounding rules, you may not receive credit for your answer.
Question 11
Refer to the scenario presented in Question 7.
What is the upper bound of the 95% confidence interval for the proportion of firms that have more than 50% female in the top 25 list?
NOTE: Enter a numerical value only, and round your response to 4 digits after the decimal point. For example, you would enter the value of .34561 (equivalent to 34.561%) as .3456 in the box below; and .34566 (or 34.566%) as .3457. If you do not follow these formatting and rounding rules, you may not receive credit for your answer.
Question 12
Refer to the scenario presented in Question 7.
For a 95% confidence interval, how large of a sample do we need if we want a margin of error of 4% in estimating the proportion of firms with more than 50% female in top 25?
For question 2-6, please look over the "descriptive conf level data analysis" attachment which is a step by step process for a similar question.
For questions 7-12, which is Descriptive Statistics Function - Proportion Confidence Level in Excel