Exam 3: Numerical Descriptive Techniques

Hours Worked per Week The following data represent the hours worked per week of a sample of 25 employees from a government department: 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. {Hours Worked per Week Narrative} Find the median hours.

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

The interquartile range is an interval of numbers starting at Q ₁ and ending at Q ₃.

Which of the following statements about the mean is not always correct?

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 first quartile.

Test Scores Suppose that an analysis of a set of test scores reveals that: Q ₁ = 45, Q ₂ = 85, Q ₃ = 105. {Test Scores Narrative} Calculate the interquartile range. What does this tell you about the data?

A basketball player has the following points for seven games: 20, 25, 32, 18, 19, 22, and 30. Compute the following measures of central location: a. mean b. median c. mode

If a data set contains an even number of observations, the median is found by taking the ____________________ of these two numbers.

Which measures of central location and variability are considered to be resistant to extreme values?

Weights of Teachers The following data represent the weights in pounds of a sample of 25 teachers: 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 Teachers Narrative} Which is a better measure of variability in the weights of the workers, the standard deviation or the coefficient of variation?

In a perfectly symmetric distribution, which of the following statements is false?

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

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} Calculate the first quartile of the ages of the uninsured retirees.

The variance is more meaningful and easier to interpret compared to the standard deviation.

The smaller the spread of scores around the mean:

The magnitude of the correlation measures the ____________________ of a linear relationship.

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} Calculate the mean age of the uninsured senior citizens

Which of the following types of data has no measure of variability?

The advantage that the coefficient of correlation has over the covariance is that the former has set lower and upper limits.

If two data sets have the same range, the distances from the smallest to largest observations in both sets will be the same.