Exam 3: Numerical Descriptive Techniques

According to the Empirical Rule, if the data form a bell shaped normal distribution approximately ____________________ percent of the observations will be contained within 3 standard deviations around the mean.

Ages of Jockeys: The following data represent the ages in years of a sample of 25 jockeys from a local race track: 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. -Construct a relative frequency distribution for the data, using five class intervals and the value 20 as the lower limit of the first class.

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%.

The middle line inside the box in a box plot represents the ____________________.

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 range of the data, and express the number in the appropriate unit.

Which of the following statements is true regarding the data set 8, 8, 8, 8, and 8?

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. -Compute the sample monthly average rent.

The ____________________ is the square root of the ____________________.

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. -Compute the lower quartile for the donations.

Which of the following statistics is a measure of central location?

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

If the coefficient of correlation r = 0, there can be no linear relationship between the dependent variable y and the independent variable x.

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. -Construct a frequency distribution for the data, using five class intervals, and the value 130 as the lower limit of the first class.

Ages of Jockeys: The following data represent the ages in years of a sample of 25 jockeys from a local race track: 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. -Find the lower quartile of the ages.

The interquartile range is a measure of variability in a set of data.

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

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. -Determine the location and value of the upper quartile of the weights.

If the standard deviations of x and y are 12.5 and 10.8, respectively, and the covariance is 118.8, then the coefficient of correlation r is 0.88.

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. -What does the histogram tell you about the distribution of the weights of workers?

If the coefficient of correlation r = $\pm$ 1, then the best-fit linear equation will actually include all of the observations.