Data Analysis Important Topics Unit wise
Unit 1: Introduction and Overview**
Data and Types of Measurement**
**Data:** Raw facts and figures collected for analysis.
**Types of Measurement Scales:**
1. **Nominal Scale** (Categories, e.g., Gender: Male/Female)
2. **Ordinal Scale** (Ordered categories, e.g., Ratings: Good, Better, Best)
3. **Interval Scale** (Equal intervals, no true zero, e.g., Temperature in °C)
4. **Ratio Scale** (True zero, e.g., Height, Weight)
Primary vs. Secondary Data** |
Methods of Collecting Primary Data**
1. **Surveys** (Questionnaires, Interviews)
2. **Observations** (Direct or Participant Observation)
3. **Experiments** (Controlled studies)
4. **Focus Groups** (Group discussions)
Population vs. Sample**
- **Population:** Entire group under study.
- **Sample:** Subset of the population.
- **Merits of Sampling:** Saves time, cost-effective.
- **Demerits:** Sampling errors may occur.
Sampling Methods**
| **Random Sampling** | **Non-Random Sampling** |
|--------------------------------|------------------------------------|
| - Simple Random Sampling | - Convenience Sampling |
| - Stratified Sampling | - Judgmental Sampling |
| - Systematic Sampling | - Quota Sampling |
Sampling Size & Distribution**
- **Sample Size Determination:** Depends on population variability, confidence level.
- **Sampling Distribution:** Probability distribution of a sample statistic (e.g., mean).
Sampling vs. Non-Sampling Errors**
| **Sampling Errors** (Due to chance) | **Non-Sampling Errors** (Human errors) |
|-------------------------------------|---------------------------------------|
| - Random fluctuations | - Data collection mistakes |
| - Reduced with larger samples | - Poor questionnaire design |
Designing a Questionnaire**
- **Key Steps:**
1. Define objectives.
2. Use simple, unbiased questions.
3. **Pretesting:** Pilot survey to check clarity.
Types of Interview Techniques**
1. **Structured Interviews** (Fixed questions)
2. **Unstructured Interviews** (Open-ended)
3. **Telephonic/Online Interviews**
Methods of Collecting Secondary Data**
- Government reports (Census, RBI bulletins)
- Journals, books, online databases (Google Scholar)
- Company annual reports
---
Unit 2: Data Processing & Representation**
Data Processing (Editing, Coding, Classification, Tabulation)**
- **Editing:** Removing inconsistencies.
- **Coding:** Assigning numerical labels (e.g., Male=1, Female=2).
- **Classification:** Grouping data into categories.
- **Tabulation:** Presenting data in tables.
### **13. Cross-Tabulation**
- Analyzes relationships between two variables.
- **Example:**
| Gender \ Income | High | Low |
|----------------|------|-----|
| Male | 30 | 20 |
| Female | 25 | 25 |
Graphical Representation**
1. **Bar Diagram:** Compares categories.
2. **Pie Chart:** Shows proportions.
3. **Histogram:** Displays frequency distribution.
4. **Ogive:** Cumulative frequency curve.
Unit 3: Statistical Analysis**
Univariate Analysis (Central Tendency, Dispersion, Skewness, Kurtosis)**
- **Mean, Median, Mode** (Central Tendency)
- **Variance, Standard Deviation** (Dispersion)
- **Skewness:** Measures asymmetry (Positive/Negative).
- **Kurtosis:** Peakedness of distribution (Leptokurtic/Platykurtic).
Bivariate Analysis (Correlation & Regression)**
- **Correlation (r):** -1 to +1 (Strength & Direction).
- **Regression Line:** \( Y = a + bX \) (Predicts Y from X).
Estimation of Population Parameters**
- **Point Estimate:** Single value (e.g., Sample Mean).
- **Interval Estimate:** Range (Confidence Interval).
---
Unit 4: Hypothesis Testing & Advanced Techniques**
Hypothesis Testing**
- **Null (H₀) vs. Alternative (H₁) Hypothesis**
- **Tests:**
1. **t-test:** Compare two means.
2. **Z-test:** Large sample mean testing.
3. **F-test:** Compare variances (ANOVA).
4. **Chi-Square:** Tests independence.
ANOVA (One-Way & Two-Way)
- **One-Way ANOVA:** Tests one factor (e.g., Teaching methods).
- **Two-Way ANOVA:** Tests two factors (e.g., Fertilizer & Irrigation).
Index Numbers**
Price Index (CPI, WPI):** Tracks price changes.
Quantity Index:** Measures production changes.
**Best of Luck!**
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