Exam 3: Numerical Descriptive Techniques

The interquartile range is the difference between the:

Find the mean number of workers.

Construct a stem and leaf display for the number of workers.

The Empirical Rule states that the approximate percentage of measurements in a data set (providing that the data set has a bell shaped distribution) that fall within two standard deviations of their mean is approximately:

If the median, median and mode are all equal, the histogram must be symmetric and bell shaped.

A data sample has a mean of 107, a median of 122, and a mode of 134. The distribution of the data is positively skewed.

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. -Describe the shape of the distribution of ages by comparing the quartiles.

The magnitude of the correlation measures the ____________________ of a linear relationship.

Ages of Senior Citizens: A sociologist recently conducted a survey of citizens 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 22 uninsured senior citizens were as follows: 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 80, 81, 86, 87, 91, 92, 94, and 97. -Calculate the mean age of the uninsured senior citizens

If the first and second quartiles are closer to each other than are the second and third quartiles, the shape of the histogram based on the quartiles is ____________________.

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. -Determine the location and value of the second quartile.

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. -Compute the sample variance, and sample standard deviation, and express the numbers in the appropriate units.

The number of hours a college student spent studying during the final exam week was recorded as follows: 6, 5, 2, 8, 7, 4, and 9. Compute the range for the data, express the number in the appropriate unit.

Ages of Workers: The ages (in years) of three groups of workers are shown below: -Compute and compare the coefficient of variation for the three samples.

Which of the following statements is true?

Compute the sample variance, and sample standard deviation.

In a bell shaped distribution, there is no difference in the values of the mean, median, and mode.

If the distribution of a data set were perfectly symmetric, the distance from Q₁ to the median would always equal the distance from Q₃ to the median in a box plot.

Salaries of Employees: The following data represent the yearly salaries (in thousands of dollars) of a sample of 13 employees 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. -Compare the mean salary with the median salary and use them to describe the shape of the distribution.

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