Making Graphs in a Spreadsheet

1. Put the independent variable in the left column, dependent to its right.
2. Select both columns including headers.
3. Insert a scatter chart (X-Y). Not a line chart — a line chart treats your x-values as labels and spaces them evenly, which silently distorts the data.
4. Add axis titles with units.
5. Add a trendline; display the equation.

What the trendline equation means

For $y=2.03x+0.14$ from an Ohm’s law run:

• The slope ($2.03$) carries the physics — here, resistance in ohms
• The intercept ($0.14$) should be near zero, and if it is not, ask why

$R^2$ is not proof

A high $R^2$ says the line fits your points. It says nothing about whether a line was the right model, or whether your data was any good. Five bad points can sit beautifully on a line.

Checklist before submitting

• Scatter chart, not line
• Both axes labelled with units
• Sensible scale — no wasted white space
• Trendline shown only where a linear relationship makes sense
• A caption stating what the graph shows