Lesson 12: Statistics & Data Analysis
Statistics is the science of collecting, organizing, and interpreting data. Understanding statistical measures helps you make sense of scores, sports, health data, and any situation where you have a set of numbers.
Key Concepts
Measures of Center
Mean: sum ÷ count. Median: middle value when sorted. Mode: most frequent value. Mean is sensitive to outliers; median is resistant. Use the median for skewed data (like salaries or home prices).
Measures of Spread
Range: max − min. Interquartile Range (IQR): Q3 − Q1 (middle 50%). Standard deviation: average distance from the mean. Small spread = data is clustered; large spread = data is scattered.
Box Plot (Box-and-Whisker)
Shows min, Q1, median, Q3, max. The box covers the middle 50% (IQR). Whiskers extend to min/max. Outliers plotted as individual dots beyond 1.5 × IQR.
Interpreting Data
Always look at the shape of the data. Is it symmetric? Skewed right (long tail right, mean > median)? Skewed left? Bimodal (two peaks)? The shape guides which statistics to use.
🔬 Interactive Lab: Statistics & Data Analysis Lab
✅ Check Your Understanding
1. Which measure of center is best when data has extreme outliers?
2. The IQR (Interquartile Range) is:
3. If most data is clustered to the left with a long tail to the right, the distribution is: