统计学课件(英文)

Information New information about the class.
Statistics is a tool for creating new understanding from a set of numbers, it gives us good descriptions about the object.
E.g., distance, height, weight, etc,.
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Qualitative and Quantitative Data
Data can also be classified as being qualitative or quantitative. The statistical analysis that is appropriate depends on whether the data for the variable are qualitative or quantitative . In general, there are more alternatives for statistical analysis when the data are quantitative.
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Kinds of Data (variables)
Qualitative (Categorical) data:
• Indicate the presence or absence in a subject of a specific characteristic, such as Gender • Values are described by words rather than numbers, or numbers without math meanings.
STATISTICAL ANALYSIS FOR BUS & ECON
Lesson 1: Introduction
Bin Wang
Statistical Analysis for Business & Economics: Spring 2011
What is Statistics?
Statistics is the science of collecting, organizing, analyzing, interpreting, and presenting data.
Observation: a single data point that represents an observed individual.
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Data
What is data (data set) in the file? What are variables in the file? What are observations in the file?
“Statistics is a way to get information from data”
Statistics
Data Data: Facts, especially numerical facts, collected together for reference or information. Information Information: Knowledge communicated concerning some particular fact.
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Scale of Measurement: Nominal
Data are labels or names used to identify an attribute of the element. A nonnumeric label or numeric code may be used. E.g., Students are classified by the school in which they are enrolled such as Business, Humanities, Education, etc,. Alternatively, a numeric code could be used for the school variable: 1 = Business, 2 = Humanities, 3 = Education, etc,.
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Scale of Measurement
Scales of measurement for a variable include: nominal, ordinal, interval, and ratio The scale determines the amount of information contained in the data. The scale indicates the data summarization and statistical analysis that are most appropriate.
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Scale of Measurement: Ratio
The data have the properties of interval data and the ratio of two values is meaningful. Contains a meaningful zero value that indicates that nothing exists for the variable at the zero point .
Definitions: Oxford English Dictionary
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Population vs. Sample
Population
• a population is the group of all items of interest to a statistics practitioner.
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Statistical Inference
Statistical inference is the process of making an estimate, prediction, or decision about a population based on a sample.
Population Sample
• frequently very large, sometimes infinite.
E.g. All 5 million Florida voters
Sample
• a sample is a set of data drawn from the population. • potentially very large, but less than the population. E.g. A sample of 765 voters exit polled on election day.
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Scale of Measurement: Ordinal
The data have the properties of nominal data and the order or rank of them is meaningful. A nonnumeric label or numeric code may be used. The difference of numeric code has no meaning. E.g., Repair service ratings: excellent, good, or poor. Alternatively, a numeric code could be used for the school variable: 1 = excellent, 2 = good, 3 = poor.
Statistics is a tool for creating new understanding from a set of numbers.
Definitions: Oxford English Dictionary
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What is Statistics?
Statistics is the science of collecting, organizing, analyzing, interpreting, and presenting data.
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Scale of Measurement: Interval
The data have the properties of ordinal data, and is measured along a scale in which each position is equidistant from one another. Interval data are always in the form of numeric numbers, can not be multiplied or divided. E.g., Level of happiness, rated from 1 to 10.
Inference
Parameter
Statistic
We can infer about a Population’s Parameters based on a Sample’s Statistics.
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Data
Data: a set of observed values of a variable or variables Variable: generally a thing that can change, characteristic of an individual that takes on various values.
“Statistics is a way to get information from data”
Statistics
Data List of last terms’ scores: 95, 82, 70, 54, 78, 69, 89,…
E.g. Class average, Proportion of class receiving A’s, Most frequent mark, Marks distribution, etc.
5源自文库
Descriptive vs. Inferential Statistics
Descriptive statistics: involves arranging, summarizing, and presenting a set of data in such a way that useful information is produced. Its methods make use of graphical techniques and numerical descriptive measures (such as averages) to summarize and present the data Inferential statistics: generalizing from a sample to a population, estimating unknown population parameters, drawing conclusions, making decisions.
Q: the salaries of Indiana Pacers’ players in the last year? (population or sample?)
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Key Statistical Concepts
Population Sample
Subset
Parameter
Population has Parameter,
Statistic
Sample has Statistic.
• A statistic is a single measure (number) used to summarize a sample data set.
• For example, the average height of 10 students in this class.