Data Types & Descriptive Statistics
📖 Chapter Overview
This chapter introduces types of data, ways to summarize them, and key concepts in
descriptive statistics. You’ll learn how to organize data into frequency distributions,
calculate central tendencies (mean, median, mode), and understand data spread using
visualizations.
🧾 Cheat Sheet
- Types of Data:
• Qualitative: Categories or labels (e.g., gender, brand)
• Quantitative: Numerical values (e.g., height, age)
- Central Tendency:
• Mean: Average value
• Median: Middle value when ordered
• Mode: Most frequent value
- Variation:
• Range: Max - Min
• Standard Deviation: Spread around the mean
- Common Visuals:
• Histogram – Shows distribution
• Boxplot – Shows spread and outliers
🧠 Practice Problems
1. Calculate the mean and median:
Dataset: 62, 65, 68, 70, 72
Answer:
- Mean = (62+65+68+70+72)/5 = 67.4
- Median = 68