Exam 3: Numerical Descriptive Measures

As a general rule, a value is considered an extreme value if its Z score is greater than 3.

TABLE 3-7 In a recent academic year, many public universities in the United States raised tuition and fees due to a decrease in state subsidies. The change in the cost of tuition, a shared dormitory room, and the most popular meal plan from the previous academic year for a sample of 10 public universities were as follows: $1,589, $593, $1,223, $869, $423, $1,720, $708, $1425, $922 and $308. -Referring to Table 3-7, what are the (absolute values of)the Z scores of the change in cost?

If a set of data is perfectly symmetrical, the arithmetic mean must be identical to the median.

Which of the arithmetic mean, median, mode, and geometric mean are resistant measures of central tendency?

In a set of numerical data, the value for Q₂ is always halfway between Q₁ and Q₃.

TABLE 3-3 The ordered array below represents the number of vitamin supplements sold by a health food store in a sample of 16 days. 19, 19, 20, 20, 22, 23, 25, 26, 27, 30, 33, 34, 35, 36, 38, 41 Note: For this sample, the sum of the values is 448, and the sum of the squared differences between each value and the mean is 812. -Referring to Table 3-3, the variance of the number of vitamin supplements sold in this sample is ________.

Which of the following statistics is not a measure of central tendency?

According to the empirical rule, if the data form a "bell-shaped" normal distribution, ________ percent of the observations will be contained within 3 standard deviations around the arithmetic mean.

The coefficient of variation measures variability in a data set relative to the size of the arithmetic mean.

If the arithmetic mean of a numerical data set is greater than the median, the data are considered to be ________ skewed.

TABLE 3-3 The ordered array below represents the number of vitamin supplements sold by a health food store in a sample of 16 days. 19, 19, 20, 20, 22, 23, 25, 26, 27, 30, 33, 34, 35, 36, 38, 41 Note: For this sample, the sum of the values is 448, and the sum of the squared differences between each value and the mean is 812. -Referring to Table 3-3, the arithmetic mean of the number of vitamin supplements sold in this sample is ________.

TABLE 3-7 In a recent academic year, many public universities in the United States raised tuition and fees due to a decrease in state subsidies. The change in the cost of tuition, a shared dormitory room, and the most popular meal plan from the previous academic year for a sample of 10 public universities were as follows: $1,589, $593, $1,223, $869, $423, $1,720, $708, $1425, $922 and $308. -Referring to Table 3-7, what is the five-number summary of the change in the cost?

TABLE 3-4 The ordered array below represents the number of cargo manifests approved by customs inspectors of the Port of New York in a sample of 35 days: 16, 17, 18, 18, 19, 20, 20, 21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23, 24, 24, 24, 25, 25, 26, 26, 26, 27, 28, 28, 29, 29, 31, 31, 32, 32 Note: For this sample, the sum of the values is 838, and the sum of the squared differences between each value and the mean is 619.89. -Referring to Table 3-4, the interquartile range of the customs data is ________.

As a general rule, a value is considered an extreme value if its Z score is less than -3.

TABLE 3-6 The rates of return of an Internet Service Provider over a 10 year period are: 10.25%, 12.64%, 8.37%, 9.29%, 6.23%, 42.53%, 29.23%, 15.25%, 21.52%, -2.35%. -You were told that the 1ˢᵗ, 2ⁿᵈ and 3ʳᵈ quartiles of female students' weight at a major university are 95 lbs, 125 lbs, and 138 lbs. What percentage of the students weigh between 95 and 138 lbs?

The median of the values 3.4, 4.7, 1.9, 7.6, and 6.5 is 1.9.

TABLE 3-10 The population of eight analysts at a software firm were asked to estimate the reuse rate when developing a new software system. The following data are given as a percentage of the total code written for a software system that is part of the reuse database. 50, 62.5, 37.5, 75.0, 45.0, 47.5, 15.0, 25.0 -Referring to Table 3-10, what are the variance and standard deviation of the total code that is part of the reuse database?

A boxplot is a graphical representation of a five-number summary.

TABLE 3-6 The rates of return of an Internet Service Provider over a 10 year period are: 10.25%, 12.64%, 8.37%, 9.29%, 6.23%, 42.53%, 29.23%, 15.25%, 21.52%, -2.35%. -You were told that the 1ˢᵗ, 2ⁿᵈ and 3ʳᵈ quartiles of female students' weight at a major university are 95 lbs, 125 lbs, and 138 lbs. What percentage of the students weigh more than 138 lbs?

In general, which of the following descriptive summary measures cannot be easily approximated from a boxplot?