دانلود رایگان کتاب بزبان انگلیسی : McGraw Hill, Schaum’s Easy Outline ofBusiness Statistics Crash Course
Statistics refers to the body of techniques used for collecting, organizing,
analyzing, and interpreting data. The data may be quantitative, with values expressed numerically, or they may be qualitative, with characteristics such as consumer preferences being tabulated. Statistics are used in business to help make better decisions by understanding the sources of variation and by uncovering patterns and relationships in business data.
Descriptive statistics include the techniques that are used to summarize
and describe numerical data for the purpose of easier interpretation.
These methods can either be graphical or involve computational analysis.
Inferential statistics include those techniques by which decisions about a statistical population or process are made based only on a sample having been observed. Because such decisions are made under conditions of uncertainty, the use of probability concepts
is required. Whereas the measured characteristics of a sample are called sample statistics, the measured characteristics of a statistical population are called population parameters. The procedure by which the characteristics of all the members of a defined population are measured is called a census. When statistical inference is used in process control, the sampling is concerned particularly with uncovering and controlling the sources of variation in the quality of the output.