Data Science

Scatter Plots: Finding Relationships

SQL Mastery Team
May 31, 2026
5 min read

Welcome to **Day 130**. Today we look at **Correlation**. Does spending more on advertising lead to more sales?

A Scatter Plot is the best way to see the answer.

The Code

ad_spend = [10, 20, 30, 40, 50]

sales = [100, 220, 310, 390, 510]

plt.scatter(ad_spend, sales)

plt.title("Ad Spend vs Sales")

plt.xlabel("Dollars Spent")

plt.ylabel("Units Sold")

plt.show()

Interpreting the Dots

  • **Upward Slope**: Positive correlation (More X = More Y).
  • **Downward Slope**: Negative correlation (More X = Less Y).
  • **A Cloud of Dots**: No correlation.

    • Adding a Trend Line

    Data Scientists often add a "Regression Line" (Line of best fit) to see exactly how strong the relationship is. We'll learn how to calculate this in Phase 4!

    Your Task for Today

    Plot "Hours Studied" vs "Test Score" for 5 hypothetical students.

    *Day 131: Beautiful Charts with Seaborn.*

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