13–9
Measures of Central Tendency集中趋势测量
• Mean均值 - the arithmetic average.
• Median中数 - the midpoint; the value below which half the values in a distribution fall.
13–10
EXHIBIT 13.4
Number of Sales Calls per Day by Salesperson
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© 2010 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
13–12
EXHIBIT 13.5
Sales Levels for Two Products with Identical Average Sales
© 2010 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
13–3
What does Statistics Mean?
• Descriptive statistics描述统计
Ø Number of people人数 Ø Trends in employment就业趋势 Ø Data数据
• Inferential statistics推断统计
Ø Make an inference about a
13–11
Measures of Dispersion离散趋势
• The Range极差（范围）
Ø The distance between the smallest and the largest
values of a frequency distribution.
• Deviation Scores离散值
population from a sample. Ø 根据一个样本对一个总体进行 推断
© 2010 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
13–8
Proportions and Top Box Scores
• Proportion
Ø The percentage of elements that meet some criterion.
• Top Box Scores
Ø Proportion of respondents who chose the most
• Probability概率
Ø The long-run relative frequency with which an event
will occur.某个事件从长期来看发生的相对频率
© 2010 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 13–5
Chapter 13 Determination of Sample Size: A Review of Statistical Theory
© 2010 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
positive choice in a multiple choice question.
v The portion that would highly recommend a business to a
friend, or the portion expressing the highest likelihood of doing business again.
LEARNING OUTCOMES
After studying this chapter, you should be able to
1. Use descriptive statistics indicating central tendency and dispersion to make inferences about a population 2. Distinguish among population, sample, and sampling distributions 3. Explain the central-limit theorem 4. Use confidence intervals to express population estimates 5. Understand the major issues in specifying sample size
13–13
EXHIBIT 13.6
Low Dispersion versus High Dispersion
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• Percentage Distribution百分比分布
Ø A frequency distribution organized into a table (or
graph) that summarizes percentage values associated with particular values of a variable.
• Inferential Statistics推断统计
Ø Make inferences about whole populations from a
sample.从一个样本推断总体
sample data.样本中的变量
• Sample Statistics样本统计量
Ø Variables in a sample or measures computed from
EXHIBIT 13.1
Frequency Distribution of Deposits
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13–4
Frequency Distributions频数分布
• Frequency Diபைடு நூலகம்tribution频数分布
Ø A set of data organized by summarizing the number
of times a particular value of a variable occurs.一组数 据通过将每个取值发生的次数来组织起来
13–2
Basic Descriptive and Inferential Statistics
• Descriptive Statistics描述统计
Ø Describe characteristics of populations or samples
描述样本或总体的特征，如年龄，性别，教育水平
• Mode众数 - the value that occurs most often.
Population Mean Sample Mean
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13–6
EXHIBIT 13.2
Percentage Distribution of Deposits
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Ø Indicate how far any observation is from the mean.