Ch 1 Introduction
1.1 Why Learn Statistics?
* Statistics is the branch of mathematics that transforms numbers into useful information for decision makers. Statistics lets you know about the risks associated with making a business decision and allows you to understand and reduce the variation in the decision-making process.
* Statistics provides you with methods for making better sense of the numbers used every day to describe or analyze the world we live in.
* Statistical methods help you understand the information contained in “the numbers” and determine whether differences in “the numbers are meaningful or ...view middle of the document...
* There are four important uses of statistics in business:
1. Using descriptive methods to visualize and summarize your data.
2. Using inferential methods to reach conclusions about a large group based on data collected from a small group.
3. Making reliable forecasts involves developing statistical models for prediction. These models use inferential methods to increase the accuracy of predictions made about future activities.
4. Improving business processes involves using managerial approaches such as Six Sigma that focus on quality improvement.
* To use descriptive and inferential methods correctly, you must also learn the conditions and assumptions required for using those methods. And because many of the statistical methods used in business must be computerized in order to be of practical benefit, you also need to know how computers can help you apply statistics in the business world.
1.3 Basic Vocabulary of Statistics
* Seven terms – variable, data, operational definition, population, sample, parameter, and statistic (singular) – identify the fundamental concepts of statistics.
* Variables are characteristics of items or individuals and are what you analyze when you use a statistical method. When used in everyday speech, variable suggests that something changes or varies, and you would expect sales, expenses, and net profit to have different values from year to year. These different values are the data associated with a variable or, more simply, the “data to be analyzed.”
* A variable is a characteristics of an item or individual.
* Data are the different values associated with a variable.
* Variables can differ for reasons other than time. Variable values are meaningless unless their corresponding variables have operational definitions. These definitions are universally accepted meanings that are clear to all associated with an analysis. Even individual values for variables sometimes need definition.
* The subject of statistics creates useful information from either populations or samples.
* A population consists of all the items or individuals about which you want to draw a conclusion.
* A sample is the portion of a population selected for analysis.
* Parameter and statistic complete the basic vocabulary of statistics.
* A parameter is a measure that describes a characteristic of a population.
* A statistic is a measure that describes a characteristic of a sample.
Ch 2 Organizing and Visualizing Data Xu, Jian
* DCOVA: Define, Collect, Organize, Visualize, and Analyze:
1. Define the variables that you want to study in order to solve a business problem or meet a business objective.
2. Collect the data from appropriate sources.
3. Organize the data collected by developing tables.
4. Visualize the data by developing charts.