Exam 4: A: Numerical Descriptive Techniques

The interquartile range is found by taking the difference between the 1st and 3rd quartiles and dividing that value by 2.

Yearly Donations The following data represent the yearly donations (in thousands of dollars)of a sample of 13 benefactors: 26.5,23.5,29.7,24.8,21.1,24.3,20.4,22.7,27.2,23.7,24.1,24.8,and 28.2. -{Yearly Donations Narrative} Compute and interpret the 90th percentile.

Which of the following measures of variability is not sensitive to extreme values?

Ages of Volunteers The following data represent the ages in years of a sample of 25 volunteers from a charitable organization: 31,43,56,23,49,42,33,61,44,28,48,38,44,35,40,64,52,42,47,39,53,27,36,35,and 20. -{Ages of Volunteers Narrative} Compute the range of the data and express the number in the appropriate unit.

Ages of Retirees A sociologist recently conducted a survey of retirees over 65 years of age whose net worth is too high to qualify for Medicaid and who have no private health insurance.The ages of 20 uninsured retirees were as follows: 65,66,67,68,69,70,71,73,74,75,78,79,80,81,86,87,91,92,94,and 97. -{Ages of Retirees Narrative} Identify the interquartile range of the ages of the uninsured retirees.What does this value tell you about the data?

Consider the following population of measurements: 162,152,177,157,184,176,165,181,170,and 163.Label and compute the variance and standard deviation.

If two data sets have the same standard deviation,they must have the same coefficient of variation.

Hours Worked per Week The following data represent the hours worked per week of a sample of 25 employees from a government department: 31,43,56,23,49,42,33,61,44,28,48,38,44,35,40,64,52,42,47,39,53,27,36,35,and 20. -{Hours Worked per Week Narrative} Compare the mean and median hours for these employees and use them to discuss the shape of the distribution.

Which measure of central location can be used for both interval and nominal variables?

Hours of Playing Video Games Suppose that the following data provide the hours of playing video games per week for a sample of 15 high school students in Roanoke,Virginia: 5,11,25,19,18,20,27,13,8,10,15,19,18,9,and 12. -{Hours of Playing Video Games Narrative} Determine the location and value of the third quartile.

A sample of 12 construction workers has a mean age of 25 years.Suppose that the sample is enlarged to 14 construction workers,by including two additional workers having common age of 25 each.Find the mean of the sample of 14 workers.

If two data sets have the same range:

The range,variance,standard deviation,and coefficient of variation are to be used only on ____________________ data.

Salaries of Office Workers The following data represent the salaries (in thousands of dollars)of a sample of 13 office workers of a firm: 26.5,23.5,29.7,24.8,21.1,24.3,20.4,22.7,27.2,23.7,24.1,24.8,and 28.2. -{Salaries of Office Workers Narrative} Compute the coefficient of variation and express the number in the appropriate unit.

The size of a sample is denoted by the letter ____________________ and the size of a population is denoted by the letter ____________________.

In a perfectly symmetric bell shaped "normal" distribution:

Which of these measures of central location is not sensitive to extreme values?

The sample mean is denoted by ____________________ and the population mean is denoted by ____________________.

The line drawn within the box of a box plot always represents the mean.

2-Year Investment Suppose you make a 2-year investment of $5,000 and it grows by 100% to $10,000 during the first year.During the second year,however,the investment suffers a 50% loss,from $10,000 back to $5,000. -{2-Year Investment Narrative} Calculate the geometric mean.