Exam 4: Numerical Descriptive Techniques

A(n) ____________________ is best defined as a set of symbols (such as people or animals) used to depict data. It often distorts the actual sizes of the items being portrayed.

Which of the following is a property of r, the coefficient of correlation?

The 5-number summary consists of the smallest observation, the first quartile, the median, the third quartile, and the largest observation.

If a data set is composed of 5 different numbers, there are ____________________ modes.

A sample of 13 college professors has a mean age of 30 years and a standard deviation of 5 years. Suppose that the sample is enlarged to 15 college professors, by including two additional professors that are each 30 years old. Will the standard deviation increase, decrease, or stay the same, and why?

NARRBEGIN: Weights of Police Officer Weights of Police Officers The following data represent the weights in pounds of a sample of 25 police officers: 164, 148, 137, 157, 173, 156, 177, 172, 169, 165, 145, 168, 163, 162, 174, 152, 156, 168, 154, 151, 174, 146, 134, 140, and 171.NARREND -{Weights of Police Officers Narrative} Determine the location and value of the upper quartile of the weights.

Which of the following statements is true?

NARRBEGIN: Salaries of Office Worker 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.NARREND -{Salaries of Office Workers Narrative} Compute the range.

In a histogram, the proportion of the total area which must be to the right of the mean is:

NARRBEGIN: Ages of Volunteers 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.NARREND -{Ages of Volunteers Narrative} Compute the coefficient of variation, and express the number in the appropriate unit.

NARRBEGIN: Ages of Retirees 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.NARREND -{Ages of Retirees Narrative} Describe the shape of the distribution of ages by comparing the quartiles.

NARRBEGIN: Ages of Retirees 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.NARREND -{Ages of Retirees Narrative} Identify the interquartile range of the ages of the uninsured retirees. What does this value tell you about the data?

The ____________________ is not as sensitive to extreme values as the ____________________.

The standard deviation is the positive square root of the variance.

A pie chart uses relative frequencies to summarize the data so including the sample size is not important.

Statisticians usually apply graphical techniques as a first step in analyzing data because we first need to know the ____________________ of the distribution.

Expressed in percentiles, the interquartile range is the difference between the 25^th and 75^th percentiles.

NARRBEGIN: Salaries of Employees 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.NARREND -{Salaries of Employees Narrative} Compare the mean salary with the median salary and use them to describe the shape of the distribution.

NARRBEGIN: Salaries of Employees 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.NARREND -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.

The ____________________ mean of n returns (or growth rates) is the appropriate mean to calculate if you wish to estimate the mean rate of return (or growth rate) for any single period in the future.