Chapter 1: Overview of Statistics
1. What is Statistics
“Statistics is a way to get information from data.” (Gerald Keller)
“Statistics is the art and science of collecting, analyzing, presenting and interpreting data.”
(Anderson et. al.)
“Statistics is a tool for creating new understanding from a set of numbers.” (Oxford English
Dictionary)
2. Data vs. Information
- Data
- Information
Average = 48.67
Min = 43.33
Max = 53.33
Range = 10
…
3. Plural or Singular?
- Statistics is the science of collecting, organizing, analyzing, interpreting, presenting data and
drawing conclusions from data.
- A statistic is a single measure, reported as a number, used to summarize a sample data set; for
example, the average height of students in the class.
4. Two Branches of Statistics
- Statistics: The branch of mathematics that transforms data into useful information for decision
makers.
+ Descriptive Statistics
Collecting, summarizing, presenting and analyzing data
+ Inferential Statistics
Using data collected from a small group to draw conclusions about a larger group
5. Descriptive Statistics
- Collect data
e.g., Survey
- Present data
e.g., Tables and graphs
- Characterize data
e.g., Sample mean =
∑ 𝑥𝑖
𝑛
6. Inferential Statistics
- Estimation
e.g., Estimate the population mean weight using the sample mean weight
- Hypothesis testing
e.g., Test the claim that the population mean weight is 65kgs
 Drawing conclusions about a population based on sample results.
7. Overview of Statistics
8. Why study statistics?
- Many working opportunities
- Better understanding of data analysis reports
- Avoiding deceptive and spurious arguments
- Improving communication and problem solving
- Developing critical and analytical thinking
…
9. Communicating with Numbers
Compare Table 1.1 and Figure 1.2. Which is more helpful in understanding U.S. trademark
activity in recent years?
10. Critical Thinking
- Statistics allows us to test an idea against empirical evidence.
- Empirical data represent data collected through observation and experiments.
- Statistical tools are used to compare prior ideas with empirical data.
11. Applications of Statistics
- Auditing: (kiểm toán): Statistical sampling procedures are used when conducting audits.
- Economics: Statistical information is used in making forecasts about the future of the economy.
- Marketing: A survey of customer preference on a product or service.
- Production: Statistical quality control charts are used to monitor the output of a production
process.
- Finance: Statistical information is used to guide an investment.
- Operations Management: Manage inventory by forecasting consumer demand.
12. Common Logical Pitfalls
- Making Conclusions about a Large Population from a Small Sample
Ex: Smoking is not dangerous. My uncle smoked all his life and lived to 100.
- Making Conclusions from Nonrandom Samples
Ex: Rock stars die young. Look at John Lennon, Michael Jackson, Whitney Houston
- Conclusions From Rare Events
Ex: Tom’s SUV rolled over. SUV is dangerous
- Using Poor Survey Methods
Ex: How many of you remember integral from your math class
13. Common Statistical Pitfalls
- Assuming a Causal Link Based on Observations
Ex: Crime rates were higher during the full moon. Full moon caused higher crime rates. (Theory
and data are reliable)
- Generalization to Individuals from Observations about Groups
Ex: Men are taller than women, so Bill is taller than Mary.
- Unconscious Bias (định kiến vô thức)
Ex: For many years, it was assumed that heart attacks were likely to occur in men than women.
- Significance (sự đáng kể) versus Importance
Ex: Men stay homes less than women