📈 Session 6.5 - Time Series Plot

📌 What Is a Time Sequence Plot?

A time sequence plot (or time series plot) is a graph that shows how a variable changes over time. The x-axis represents time (e.g., test sequence, hours, years), and the y-axis represents the observed values. This visualization helps detect:

• Trends (upward/downward)
• Cycles or seasonality
• Sudden shifts or unusual changes

🧾 Raw Data: Alloy Compressive Strength (80 Tests)

📊 Time Series Plot

🔍 Interpretation

This plot represents compressive strength values from 80 alloy samples tested sequentially.

• Notice if the line trends up (increasing strength) or down (decreasing strength).
• Look for sharp jumps — possible process errors or improvements.
• If values fluctuate consistently up and down, it may indicate a cyclical pattern.

🧠 Practice Question

Suppose an engineer suspects that after test #50, something changed in the process.

Question: Do the compressive strengths appear higher or lower after test #50?

Show Answer