Science data interpretation and experimental design

Reading charts, tables, and scientific graphs

You’ll see a lot of charts and graphs on the GED science test, and your job is to pull numbers and patterns out of them, not to remember facts.

1. What you can get from a data display

Most charts/graphs let you answer three main kinds of questions:

• Exact numbers
  Values at specific points.

• Trends
  Whether something is going up, down, or staying about the same.

• Comparisons
  Which is greater/smaller, faster/slower, or more/less.

Example: Reading a table

Imagine you see this in a question:

You might be asked:

• “On which day was the temperature highest?”

  • Look at the Temperature column: 18, 20, 24, 22 → highest is 24 on Wed.

• “Between which two days did the temperature decrease?”

  • Check day-to-day:
    • Mon→Tue: 18→20 (increase)
    • Tue→Wed: 20→24 (increase)
    • Wed→Thu: 24→22 (decrease)

Example: Using a bar graph

Suppose you see a bar graph of plant heights after 4 weeks:

Questions you might answer:

• “Which fertilizer led to the tallest plants?”

  • Longest bar = A (15 cm).

• “How much taller were plants with fertilizer A than with none?”

  • Subtract: $15 - 10 = 5$ cm taller.

Example: Using a line graph

Line graphs are great for seeing change over time.

Say you have:

From this, you can see:

• From week 1 to 3: increases (100 → 200 → 300).
• From week 3 to 4: decreases (300 → 250).
• Total increase from week 1 to week 4: $250 - 100 = 150$ bacteria.