Exam 3: Numerical Descriptive Measures

The Z score of an observation can never be negative.

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?

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 observations is 448, the sum of the squares of the observations is 13,356, and the sum of the squared differences between each observation and the mean is 812. -Referring to Table 3-3, the coefficient of variation of the number of vitamin supplements sold in this sample is ________ percent.

TABLE 3-2 The data below represent the amount of grams of carbohydrates in a serving of breakfast cereal in a sample of 11 different servings. -Referring to Table 3-2, the five-number summary of the carbohydrate amounts consists of ________, ________, ________, ________, ________.

TABLE 3-5 The rate of return of a Fortune 500 company over the past 15 years are: 3.17%, 4.43%, 5.93%, 5.43%, 7.29%, 8.21%, 6.23%, 5.23%, 4.34%, 6.68%, 7.14%, -5.56%, -5.23%, -5.73%, -10.34% -Referring to Table 3-5, compute the geometric mean rate of return for the first four years.

TABLE 3-1 Health care issues are receiving much attention in both academic and political arenas. A sociologist recently conducted a survey of citizens over 60 years of age whose net worth is too high to qualify for Medicaid and have no private health insurance. The ages of 25 uninsured senior citizens were as follows: -Referring to Table 3-1, what type of shape does the distribution of the sample appear to have?

TABLE 3-6 The rate 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%. -Referring to Table 3-6, compute the arithmetic mean rate of return.

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.

You were told that the 1st, 2nd, and 3rd quartiles of 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?

TABLE 3-2 The data below represent the amount of grams of carbohydrates in a serving of breakfast cereal in a sample of 11 different servings. -Referring to Table 3-2, the third quartile of the carbohydrate amounts is ________ grams.

According to the Chebyshev rule, at least what percentage of the observations in any data set are contained within a distance of 2 standard deviations around the mean?

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

TABLE 3-7 In the 2009-2010 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 2008-2009 academic year for a sample of 10 public universities were as follows: $1589, $593, $1223, $869, $423, $1720, $708, $1425, $922 and $308. -Referring to Table 3-7, what is the mean and median change in the cost?

In exploratory data analysis, a boxplot can be used to illustrate the median, quartiles, and extreme values.

TABLE 3-6 The rate 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%. -Referring to Table 3-6, compute the geometric mean rate of return for the first three years.

In perfectly symmetrical distributions, which of the following is NOT a correct statement?

TABLE 3-5 The rate of return of a Fortune 500 company over the past 15 years are: 3.17%, 4.43%, 5.93%, 5.43%, 7.29%, 8.21%, 6.23%, 5.23%, 4.34%, 6.68%, 7.14%, -5.56%, -5.23%, -5.73%, -10.34% -Referring to Table 3-5, what is the range of the rate of return?

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 observations is 448, the sum of the squares of the observations is 13,356, and the sum of the squared differences between each observation and the mean is 812. -Referring to Table 3-3, what type of shape does the distribution of the sample appear to have?

TABLE 3-2 The data below represent the amount of grams of carbohydrates in a serving of breakfast cereal in a sample of 11 different servings. -Referring to Table 3-2, construct a boxplot for the carbohydrate amounts.

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 observations is 448, the sum of the squares of the observations is 13,356, and the sum of the squared differences between each observation and the mean is 812. -Referring to Table 3-3, the variance of the number of vitamin supplements sold in this sample is ________.