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CHAPTER 4 SECTION 7-8: NUMERICAL DESCRIPTIVE TECHNIQUES
MULTIPLE CHOICE
260. Which of the following characteristics does a histogram help you identify?
a. The shape of distribution.
b. The approximate center of a distribution.
c. The amount of spread in a distribution.
d. All of these choices are true.
ANS: D
PTS: 1
REF: SECTION 4.7-4.8
261. The shape of a distribution helps answer which question about the data?
a. Where is the approximate center of the distribution?
b. Are the observations close to one another, or are they widely dispersed?
c. Is the distribution symmetric?
d. All of these choices are true.
ANS: D
PTS: 1
REF: SECTION 4.7-4.8
262. Which of the following is correct about the shape of a distribution?
a. The shape can show you how many modes there are.
b. The shape can help you determine the approximate center of the distribution.
c. The shape can help you determine whether the data are close or spread out.
d. All of these choices are true.
ANS: D
PTS: 1
REF: SECTION 4.7-4.8
263. A scatter diagram reveals a strong positive linear relationship between oil and gasoline prices. Which
of the following numerical techniques will not give us more detailed information about this
relationship?
a. Coefficient of determination
b. Coefficient of correlation
c. Coefficient of variation.
d. All of these choices help us describe this relationship.
ANS: C
PTS: 1
REF: SECTION 4.7-4.8
TRUE/FALSE
264. Statisticians typically apply graphical techniques as a first step in a data analysis because we first need
to know the shape of the distribution.
ANS: T
PTS: 1
REF: SECTION 4.7-4.8
265. Graphical and numerical techniques, such as histograms and least squares lines provide identical
information.
ANS: F
PTS: 1
REF: SECTION 4.7-4.8
This edition is intended for use outside of the U.S. only, with content that may be different from the U.S. Edition. This may not be resold,
copied, or distributed without the prior consent of the publisher.
266. The coefficient of correlation and the least squares line both describe the relationship between two
interval variables.
ANS: T
PTS: 1
REF: SECTION 4.7-4.8
267. The precision provided by the numerical techniques (mean, median, and standard deviation) provides
more useful information than graphical techniques (histograms and box plots) alone.
ANS: T
PTS: 1
REF: SECTION 4.7-4.8
COMPLETION
268. Scatter diagrams, covariance, and the coefficient of correlation are useful techniques for detecting
relationships between two ____________________ variables.
ANS: interval
PTS: 1
REF: SECTION 4.7-4.8
269. Statisticians usually apply graphical techniques as a first step in analyzing data because we first need
to know the ____________________ of the distribution.
ANS: shape
PTS: 1
REF: SECTION 4.7-4.8
270. Box plots and medians work well to describe ____________________ data, while histograms and
means work well to describe ____________________ data.
ANS: skewed; symmetric
PTS: 1
REF: SECTION 4.7-4.8
271. ____________________ techniques give you the big picture of a distribution, and
____________________ techniques give you more precise details.
ANS: Graphical; numerical
PTS: 1
REF: SECTION 4.7-4.8
272. We can frequently make several inferences about the nature of the data from the
____________________ of its histogram.
ANS: shape
PTS: 1
REF: SECTION 4.7-4.8
SHORT ANSWER
273. What statistics and graphs can you use to answer the following question: Where is the approximate
center of the distribution?
This edition is intended for use outside of the U.S. only, with content that may be different from the U.S. Edition. This may not be resold,
copied, or distributed without the prior consent of the publisher.
ANS:
The median is a better measure of center for skewed data, and the mean works well for symmetric
data. If the data is skewed, a box plot can show you where the median is. If the data is symmetric, a
histogram can give you an idea where the mean is.
PTS: 1
REF: SECTION 4.7-4.8
274. What statistics and graphs can you use to answer the following question: Are the observations close to
one another, or are they widely dispersed?
ANS:
The standard deviation can tell you whether the observations are close to or spread out from the
middle. The interquartile range tells how far apart them middle 50% of the data are, and works
especially well for skewed data. A histogram and a box plot can show you how close together/spread
out the data appear visually.
PTS: 1
REF: SECTION 4.7-4.8
275. What statistics and graphs can you use to answer the following questions: Is the distribution unimodal,
bimodal, or multimodal? If there is more than one mode, where are the peaks, and where are the
valleys?
ANS:
A histogram can show you the number of modes of a distribution, as well as where they are located. A
box plot cannot tell you where any of the modes of a distribution are, or even how many might exist. It
just shows you distances between certain milestones in the distribution, such as the five-number
summary. This is a drawback of a box plot.
PTS: 1
REF: SECTION 4.7-4.8
276. What statistics and graphs can you use to answer the following question: Is the distribution symmetric?
If not, is it skewed? If symmetric, is it bell shaped?
ANS:
A histogram can show you whether a distribution is symmetric, positively skewed, negatively skewed,
or has a different shape. If the data is symmetric, a histogram can tell you whether the data is bell
shaped, bimodal, or uniform, etc. A box plot can also show you whether a distribution is symmetric,
negatively skewed or positively skewed. However, it can't tell you what the exact shape is, if the data
are found to be symmetric. For example, a box plot cannot tell you whether a symmetric data set is
unimodal or bimodal. This is a drawback of a box plot.
PTS: 1
REF: SECTION 4.7-4.8
277. What statistics and graphs can you use to look for a relationship between two interval variables?
ANS:
Scatter diagrams, covariance, the coefficient of correlation, and the coefficient of determination are
useful techniques for detecting relationships between two interval variables.
PTS: 1
REF: SECTION 4.7-4.8
This edition is intended for use outside of the U.S. only, with content that may be different from the U.S. Edition. This may not be resold,
copied, or distributed without the prior consent of the publisher.