The science of collecting, organizing, presenting, analyzing, and interpreting data to assist in making more effective decisions.
收集、整理、显示、分析、解释。为了做出更有效的决策
Types
Descriptive Statistics 描述性统计学
Definition
methods of organizing, summarizing, and presenting data in an informative way. 更实用
Inferential Statistics 推断性统计学
Definition
A decision, estimate, prediction, or generalization about a population, based on a sample.
Population整体
Definition
A population is the entire set of individuals or objects of interest, or the measurements obtained from all individuals or objects of interest. 全部
Sample样本
Definition
A sample is a portion, or part, of the population of interest. 部分
Types of Variables 变量
Qualitative or attribute variable 定性变量
Definition
the characteristic being studied is nonnumeric
非数值型的
Examples
gender, religious affiliation, type of automobile owned, state of birth, and eye color,etc.
Quantitative variable 定量变量
Definition
information is reported numerically.数值型
Examples
balance in your checking account支票账户余额，minutes remaining in class, or number of children in a family.
Types
Discrete variables 离散型变量
Definition
Discrete variables can only assume certain values, and there are usually “gaps” between values. 特定值、之间有间隔
Examples
the number of bedrooms in a house, or the number of hammers sold at the local Home Depot (1,2,3,…,etc).
Continuous variable连续性变量
Definition
Continuous variable can assume any value within a specified range.在给定区间内可以取到任意一个值
Examples
the pressure in a tire轮胎的压力，the weight of a pork chop猪排的重量，or the height of students in a class. 学生的身高
Four level of Measurement
(从1.到4. 逐级升高）
1.Nominal level定类
2.Ordinal level定序
3.Interval level定距
4.Ratio level定比
Chapter 2
Describing Data描述数据
Frequency Tables频数表
Types种类
Frequency Table频数表
Definition定义
A grouping of qualitative data 定性数据into mutually exclusive classes 相互排斥的类别showing the number of observations in each class.显示每个类别的观察次数（定性）
Bar Charts柱状图/条形图
Definition
A graph in which the classes are reported on the horizontal axis 类别在横轴体现and the class frequencies on the vertical axis. 类别频率在竖轴体现The class frequencies are proportional to the heights of the bars.频率与条的高度成正比
Pie Charts饼图
Definition
A chart that shows the proportion or percent that each class represents of the total number of frequencies.显示每个类别在总频率数的所占比例或百分比
Frequency Distributions频数分布
Definition
A grouping of data数据into mutually exclusive classes showing the number of observations in each class.（定量）
Relative Class Frequencies 相对类频率
Class frequencies can be converted to relative class frequencies to show the fraction of the total number of observations in each class.
A relative frequency captures the relationship between a class total and the total number of observations.类别总数和观察总数之间的关系
Frequency Distribution频率分布
Class interval类间隔
The class interval is obtained by subtracting the lower limit of a class from the lower limit of the next class.一个类的下限 减 上一个类的下限
Class frequency 类频
The number of observations in each class.每个类中的观察次数。
Class midpoint组中值
midpoint: A point that divides a class into two equal parts. This is the average of the upper and lower class limits. （a+b）/2
Graphic Presentation 图表展示
Constructing a Frequency Table
Three graphic forms of a Frequency Distribution
Histogram直方图
Frequency Polygon频数多边形
Cumulative Frequency Polygon
累计频数多边形图表
Chapter 3
Describing Data
Numerical Measures
Central Tendency（measures of location)
观测值的中心位置
The arithmetic mean算术平均数
Population Mean
Sample mean
The weighted mean加权平均数
见图片
the mean平均值
The median中位数
见图片
The mode众数
见图片
Measures of Dispersion
数据离散度
range距离
and
the standard deviation标准差
切比雪夫定理和经验法则
Chapter 4
Chapter 5
Chapter 6
Chapter 7
Chapter 8
Chapter 9
Chapter 10
Chapter 11
Two-Sample Tests of Hypothesis 双样本假设检验
Test a hypothesis that two independent population means with known population standard deviations are equal.检验一个假设，即具有两个标准差相等的 独立的已知人口均值。
Carry out a hypothesis test that two population proportions are equal.进行一个关于两个人口比例相等的假设检验。
Conduct a hypothesis test that two independent population means are equal,assuming equal but unknown population standard deviations.进行一个假设检验，假定两个独立整体的均值相等，但整体标准差未知。
Dependent vs. Independent Samples
Dependent Samples 相依样本
Definition
Dependent samples are samples that are paired or related in some fashion. 以某种方式配对或相关联的样本。
