Exam 3: Numerical Descriptive Techniques

The ____________________ mean is used whenever we wish to find the "average" growth rate, or rate of change, in a variable over time .

Which of the following summary measures cannot be easily approximated from a box plot?

The ____________________ is calculated by finding the middle of the data set, when the data are ordered from smallest to largest.

The mean is affected by extreme values but the median is not.

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. {Weights of Police Officers Narrative} What does the histogram tell you about the distribution of the weights of workers?

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 median.

Which of the following statements about the median is not true?

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. {Ages of Senior Citizens Narrative} Explain why there is no mode for this data set.

Ages of Workers The ages (in years)of three groups of workers are shown below: {Ages of Workers Narrative} Compute and compare the ranges for the three groups.

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 range.

The 10th ____________________ is the value for which 10% of the observations are less than that value.

When extreme values are present in a set of data, which of the following descriptive summary measures are most appropriate?

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

Is it possible for the standard deviation of a data set to be larger than its variance? Explain.

The Empirical Rule states that the percentage of observations in a data set (providing that the data set is bell shaped)that fall within one standard deviation of their mean is approximately 75%.

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. {Weights of Police Officers Narrative} a. Construct a box plot for the weights. b. Are there any extreme values? c. What does the box plot tell you about the distribution of the data?

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

Consider the following data: a. Calculate the covariance and the coefficient of correlation for the sample. b. What do these statistics tell you about the relationship between x and y ?

m is a population parameter and is a sample statistic.

Strip Mall Rent Monthly rent data in dollars for a sample of 10 stores in a small town in South Dakota are as follows: 220, 216, 220, 205, 210, 240, 195, 235, 204, and 250. {Strip Mall Rent Narrative} Compute the sample monthly average rent.