- Your college or university wishes to obtain reliable information about student perceptions of administrative communication. Describe how to design a sampling plan for this situation based on your knowledge of the structure and organization of your college or university. How would you implement simple random sampling, stratified sampling, and cluster sampling for this study? What would be the pros and cons of using each of these methods?
- Number the rows in the Excel file Credit Risk Data to identify each record. The bank wants to sample from this database to conduct a more-detailed audit. Use the Excel Sampling tool to find a simple random sample of 20 unique records.
6.6 In determining automobile mileage ratings, it was found that the mpg in the city for a certain model is normally distributed, with a mean of 30 mpg and a standard deviation of 1.0 mpg. Suppose that the car manufacturer samples 5 cars from its assembly line and tests them for mileage ratings.
- What is the distribution of the mean mpg for the sample?
- What is the probability that the sample mean will be greater than 31 mpg?
- What is the probability that the sample mean will be less than 29.5 mpg?
6.11 A bank sampled its customers to determine the proportion of customers who use their debit card at least once each month. A sample of 50 customers found that only 12 use their debit card monthly. Find 95% and 99% confidence intervals for the proportion of customers who use their debit card monthly. Use the appropriate formula and verify your result using the Confidence Intervals workbook.