Exam 3: Numerical Descriptive Techniques

Milk Demand A supermarket has determined that daily demand for milk containers has an approximate bell shaped distribution, with a mean of 55 containers and a standard deviation of six containers. {Milk Demand Narrative} How often can we expect between 49 and 61 containers to be sold in a day? (Give a percentage.)

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.

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.

The value for Q ₃ can never be smaller than the value for Q ₁.

The price-earnings ratios of a sample of stocks have a mean value of 13.5 and a standard deviation of 2. If the ratios have a bell shaped distribution, what can we say about the proportion of ratios that fall between a. 11.5 and 15.5? b. 9.5 and 17.5? c. 7.5 and 19.5?

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

The ____________________ uses both the mean and the standard deviation to interpret standard deviation for bell shaped histograms.

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 median.

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

A population with 200 elements has a variance of 20. From this information, it can be shown that the population standard deviation is 10.

The range is considered the weakest measure of variability.

In a positively skewed distribution:

The interquartile range will always exceed that of the range.

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} Calculate and interpret the interquartile range.

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.

The following data represent the number of children in a sample of 10 families from a certain community: 4, 2, 1, 1, 5, 3, 0, 1, 0, and 2. a. Compute the range. b. Compute the variance. c. Compute the standard deviation. d. Compute the coefficient of variation. e. Explain why in this case range > variance > standard deviation > coefficient of variation.

Which of the following statements is true?

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

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

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. {Ages of Jockeys Narrative} Find the lower quartile of the ages.