Bài giảng Probability & Statistics - Lecture 1 - Bùi Dương Hải

PROBABILITY & STATISTICS (Bachelor Degree) Bui Duong Hai Faculty of Mathematical Economics - NEU haibd@neu.edu.vn www.mfe.edu.vn/buiduonghai STATISTICS FOR MANAGEMENT– Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 1 Materials  TEXT BOOK: [1] Anderson, Sweeney, Williams, Camm, Cochran (2017), Statistics for Business and Economics, 12th Edition, South-Western. [2] Linda H., John F. (2013), Applied Statistics for Business and Management using Microsoft Excel, Springer. [3] Paul Newbold, William L. Carlson, Betty M. Thorne (2013), Statistics for Business and Economics, 8th Edtion, Pearson. PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 2 Materials  SOFTWARE: • Microsoft Excel - Data Analysis Toolpak • IBM SPSS Package  Calculator  DATA and Others: www.mfe.edu.vn/buiduonghai : *Program* > *Class* • Bui Duong Hai (2016), Microsoft Excel Using for Statistics Practice, NEU (Vietnamese version) PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 3 LECTURE 1 - INTRODUCTION  Concepts  Branches of Statistics  Elements of Statistics  [1] Chapter 1, pp. 1 – 29.  [2] Chapter 1, pp. 1 – 9. PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 4 What is statistics ? Opinion Statistics It seems that there are more female students than male in the NEU. In total of 16,000 NEU students, there are 10,000 females (62.5%) and 6,000 males (37.5%). In general, the older the customer is, the less money they spend on high- tech products. PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 5 Age 20-29 30-39 40+ Average expense 35 28 23 Why statistics ? Problem Statistics Should we invest in high- tech stocks rather than other industries? Whether the year 2018 would be strong growth period of the stock market in Vietnam? PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 6 0% 5% 10% 15% 20% Construction High-tech Manufaturing Retail Return (%) Statistics to  Understand business environment  Provide information for decision making  Predict, forecast   Apply in all aspect of business, economics, management. PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 7 Statistics is the fact ?  Yes, but No !  Information for Statistics  Statistics maybe biased  Without testing for correction of statistics, decision would be wrong  Statistics problem:  Accuracy of data?  Appropriate method? PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 8 Example  Studying capacity of classes?  Compare popularity of two topics / trade marks / artists?  Evaluate investment projects?  Question: Other statistical issues in your life ? PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 9 Statistics  Gathering data  Processing data  Presenting information  Analyzing data  higher level informatic results  Inference information PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 10 Statistics Primary Information (Data) Superior Information (Result) Branches of Statistics  Two main branches:  Descriptive Statistics: organize, summarize, present data in convenient and informative way.  Inferential Statistics: predict, forecast, verify knowledge by analyzing data.  This course: fundamental methods and techniques of descriptive and inferential statistics in management. PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 11 Data Sources  Primary and Secondary data  Primary data: observed / collected by the investigator for a specific purpose • From survey, questionnaire, records  Raw data  Process  Advantages: relevant to the purpose, flexible, deep information  Disadvantages: • Costly, not response, missing information • Errors by measures, surveying method, PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 12 Data Sources  Secondary data: collected in the past or other parties • Government, organizations, institutes, • Published, on the internet, buying  Collect, process for purposes  Advantages • Official, high accuracy • Bigger data, less expense  Disadvantages • May not relevant to the purpose • Cannot survey further information PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 13 Population and Sample  Population: set of all interested elements  Population size: N, maybe infinite  Value from population: parameter  Sample: subset of Population  Sample size: n, finite  Value from sample: statistic PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 14                  Data set  Includes: Observation (each row) – Variable (each column) – Value (each cell) PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 15 Variables No. Name Sex Age English Mark Maths Score O b se rva tio n s 1 Anderson M 19 A 8 2 Becky F 20 C 9 3 Charles M 20 B 7 . . Types of Variable  Qualitative and Quantitative  Qualitative (Categorical): Nominal and Ordinal • Nominal: incomparable values Ex.: Name, Address, Study Specification, • Ordinal: comparable values but not calculated Ex.: Rank, Level, Shoe size, • Special: Binary (dichotomous) variable: Ex.: Yes/No, Pass/Fail, Gender,  Qualitative: could be coded into number PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 16 Types of Variables  Quantitative (Cardinal, Scale) variable: • Discrete vs Continuous  Discrete: Number of items, Score, Age  Continuous: Time, Length, • Interval vs Ratio:  Interval: plus, minus only  Ratio: divide, multiple are acceptable  Classification of Quantitative variable is not important PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 17 Types of Variables PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 18 Qualitative (Categorical) Quantitative (Scale) Nominal Ordinal Discrete Continuous Listing, Grouping Listing, Grouping, Sorting, Maybe ± Listing, Grouping, Sorting Math operation: ±, , ÷, Interval Ratio Coded by numbers Used to rank Types of Variables PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 19 More than 2 value ? Binary Nominal Ordinal Scale No No No Yes Yes Yes Comparable ? Can be Calculated ? Summarize  Concept of Statistics  Branches of Statistics  Primary and Secondary data  Population and Sample  Observation, Variable, Value  Types of Variable PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 20 Exercise  [1] Chapter 1 (p.22): 2, 4, 6, 7, 8, 9, 11, 12  Reading: VHLSS data • Variables • Province code  Reading: SME Main questionnaire • Type of variables PROBABILITY & STATISTICS – Bui Duong Hai – NEU – www.mfe.edu.vn/buiduonghai 21