Chapter 1 Data and Statistics

Chapter 1: Data and Statistics

  • Dr. Pham Phuong Ngoc

CONTENT

  1. Applications in Business and Economics

  2. Data

  3. Data Sources

  4. Descriptive Statistics

  5. Statistical Inference

I. Applications in Business and Economics

  • The U.S. housing market has experienced a significant slowdown, with housing sector activity dropping by 30%-40% over the past 18 months.

II. What is Statistics?

  • Definition: Statistics is the art and science of collecting, analyzing, presenting, and interpreting data.

  • Purpose: Provides a method for extracting meaningful information from data.

    • Statistics ➔ Data ➔ Information.

III. Applications of Statistics

  • Accounting: Statistical sampling is utilized in public accounting for client audits.

  • Marketing: Retail scanners gather data for marketing research applications.

  • Finance: Financial analysts employ statistical information for investment recommendations.

  • Production: Quality control charts monitor production processes.

  • Economics: Economists utilize statistics for economic forecasts.

IV. Data

  • Data definition: Facts and figures collected, analyzed, and summarized for interpretation.

  • Data Set: The collection of all data from a study.

V. Elements, Variables, and Observations

  • Elements: Entities on which data are collected.

  • Variables: Characteristics of interest for an element.

  • Observations: Set of measurements for a specific element.

  • Total Data Values: Calculated as the number of elements multiplied by the number of variables.

VI. Example Company Data

Company

Stock Exchange

Annual Sales (M)</p></th><th><p>EarningsperShare(M)</p></th><th><p>Earnings per Share ()

NQ


73.1

0.86

N


74.0

1.67

N


365.7

0.86

NQ


111.4

0.33

N


17.6

0.13

VII. Scales of Measurement

  • Types of Scales:

    1. Nominal: Data used as labels for attributes (e.g., classification by school).

    2. Ordinal: Order or rank is meaningful (e.g., class standings: Freshman, Sophomore).

    3. Interval: Differences between values are meaningful, fixed unit of measure (e.g., SAT scores).

    4. Ratio: All properties of interval data plus meaningful ratios (e.g., credit hours earned).

VIII. Exercises on Scales of Measurement

  • Identify the scale of measurement for:

    • a. Student IQ ratings

    • b. Distance traveled to class

    • c. State of birth

    • d. Academic class standing

    • e. Study hours per week

IX. Data Classification

  • Qualitative Data: Categorical data grouped by specific categories.

  • Quantitative Data: Numeric data indicating quantity, includes:

    • Discrete Variable: Countable values.

    • Continuous Variable: Measurable values.

  • Statistical analysis varies based on whether data is qualitative or quantitative.

X. Data Types

  • Cross-Sectional Data: Collected at a single point in time (e.g., building permits in June 2007).

  • Time Series Data: Collected over several periods (e.g., permits issued over 36 months).

XI. Data Sources

  • Existing Sources:

    • World Bank, IMF, UN databases, business databases, government agencies.

XII. Data Acquisition Considerations

  • Time Requirement: Data searching can be time-consuming.

  • Cost: Charge for acquiring certain data.

  • Data Quality: Careless data collection can lead to inaccuracies.

XIII. Descriptive Statistics

  • Defined as methods for summarizing and presenting data using tables, graphs, and numerical summaries.

XIV. Example of a Data Set

  • Data Set for 60 Nations in WTO shows per capita GDP and Fitch ratings.

XV. Inferential Statistics

  • Analyzes data to draw conclusions about a population based on a sample.

  • Key concepts:

    • Population: The complete set of elements of interest.

    • Sample: A subset of the population.

XVI. Statistical Inference

  • Aims to understand a population's characteristics by analyzing a sample.

XVII. Exercises on Statistical Inference

  • Determine if questions refer to population or sample:

    • a. Average MPG of all CSULB students.

    • b. Percent of 500 students supporting off-shore drilling.

    • c. Range of income in Long Beach.

    • d. Average weight of farm-raised chickens.

XVIII. Closing

  • Quote by Timo Elliott: "If you don't reveal some insights soon, I'm going to be forced to slice, dice, and drill!"