Exam 4: Numerical Descriptive Techniques

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 and interpret the 90th percentile.

Which of the following is a property of the slope, b₁?

If the observations are in the millions, a standard deviation of 10 would be considered small.If the observations are all less than 50, a standard deviation of 10 would be considered large.

The size of a sample is denoted by the letter ____________________ and the size of a population is denoted by the letter ____________________.

Which of the following measures of variability is not sensitive to extreme values?

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} What does the value of the third quartile tell you?

According to the Empirical Rule, if the data form a bell shaped normal distribution, approximately ____________________ percent of the observations will be contained within 2 standard deviations around the mean.

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} Determine the location and value of the second quartile.

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} What does the value of the first quartile tell you?

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

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 coefficient of variation and express the number in the appropriate unit.

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} What is the mode?

The units for the variance are the same as the units for the original data (for example, feet, inches, etc.).

Chebysheff's Theorem applies only to data sets that have a bell shaped distribution.

The denominator in the calculation of the sample covariance, cov (x,y), is:

The annual percentage rates of return over the past 10 years for two mutual funds are as shown below.Which fund would you classify as having the higher level of risk?

In a histogram, the proportion of the total area which must be to the left of the median is less than 0.50 if the distribution is negatively skewed.

The interquartile range will always exceed that of the range.

Expressed in percentiles, the fifth decile is the 50th percentile or the median.

The first and second quartiles of a data set can never be equal.