Numerical Descriptive Measures 99
122. Referring to Table 3-9, the middle 50% of the change in the cost is spread over what value?
ANSWER: $832
TYPE: PR DIFFICULTY: Moderate KEYWORDS: interquartile range
123. Referring to Table 3-9, what is the coefficient of variation of the change in cost?
ANSWER: 50.29%
TYPE: PR DIFFICULTY: Moderate KEYWORDS: coefficient of variation
124. Referring to Table 3-9, what are the (absolute values of) the Z scores of the change in cost?
ANSWER:
1.24, 0.78, 0.50, 0.22, 1.13, 1.51, 0.55, 0.91, 0.11, 1.36 TYPE: PR DIFFICULTY: Moderate KEYWORDS: Z scores
125. Referring to Table 3-9, are the data skewed? If so, how?
ANSWER:
skewed to the right
TYPE: PR DIFFICULTY: Moderate KEYWORDS: shape
TABLE 3-10
The following table represents the assets in billions of dollars of the five largest bond funds. Bond Fund Assets (Billions $) Vanguard GNMA 19.5 Vanguard Total Bond Mkt. Index 16.8 Bond Fund of America A 13.7 Franklin Calif. Tax-Free Inc. A 12.8 Vanguard Short-Term Corp. 10.9 126. Referring to Table 3-10, what is the mean for this population of the five largest bond funds?
ANSWER: $14.74 billions
TYPE: PR DIFFICULTY: Easy KEYWORDS: population mean
Copyright ? 2010 Pearson Education, Inc. Publishing as Prentice Hall
100 Numerical Descriptive Measures
127. Referring to Table 3-10, what are the variance and standard deviation for this population?
ANSWER:
9.2984 squared billion dollars, $3.0493 billions, respectively TYPE: PR DIFFICULTY: Moderate
KEYWORDS: population variance, population standard deviation
TABLE 3-11
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
128. Referring to Table 3-11, what is the mean percentage of the total code that is part of the reuse
database?
ANSWER: 44.69
TYPE: PR DIFFICULTY: Easy KEYWORDS: population mean
129. Referring to Table 3-11, what are the variance and standard deviation of the total code that is
part of the reuse database?
ANSWER:
324.12 and 18.00, respectively
TYPE: PR DIFFICULTY: Moderate
KEYWORDS: population variance, population standard deviation
Copyright ? 2010 Pearson Education, Inc. Publishing as Prentice Hall