How to Plot a Standard Curve in Excel

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Microsoft's prolific spreadsheet creator, Excel, has been used to create digital art, stop-motion animation, Sudoku puzzles, a working flight simulator and even a fully functioning version of Pac-Man. The point is, it's pretty darn flexible software, whether you're a gamer, an artist, or a scientist. If you fall into the latter category, there's a pretty good chance you'll cross paths with standard curves some day – when you do, turn to Excel, your new favorite standard curve generator.

What Is a Standard Curve?

At its core, the standard curve is a visual representation of the relationship between two quantities, taking its Excel form as a simple line graph.

When creating a standard curve – whether using Excel, any other program or the ancient techniques known as "pen" and "paper" – you start with a set of standards or data points of a known quantity, which you will relate to another set of data points that are objectively measurable. When you graph the relationship between those two groups, you have a beautifully curvy line graph on your hands – that's your standard curve.

Make Your Standard Curve Graph

On your Excel data table, start with a few columns. Your first column, Column A, will be your known quantities while the second column, Column B, lists the data points you're measuring them against. Make sure you have an equal number of data points.

Select Column A, which will serve as your standard curve's x axis, and Column B, which'll be your y axis. Once they're both selected, click the "Insert" tab on Excel's toolbar, then find the "Insert Scatter (X, Y) or Bubble Chart" option, located in the "Charts" section, and pick the scatter plot option by clicking on the symbol that looks like a scatter plot – go with the scatter plot that doesn't have any connecting lines. When the graph pops up, you can title it, delete grid lines and create labels for each axis.

However, you're still missing an essential part of your standard curve in Excel – the "line" part of the line graph. Just right-click and choose "Add Trendline" to complete your standard curve.

More to Know

When you're dealing with a bunch of different data groups that represent one category of data – either the known quantity or the points of comparison – select the cells and use Excel's averaging function (performed by typing "=average" at the top of a new column) to come up with an average to use in your standard curve graph.

Similarly, you can use Excel to automatically assess standard deviation. In the column next to your averages, type "=stdev" and choose the "STDEVP" option that appears from the menu and enter your preferred data points in the open parenthesis.

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