How to Find Standard Deviation on the TI–84

An easy-to-follow guide on how to find the standard deviation (sd) on a TI-84 calculator

Written by Nicole Levine, MFA

Last Updated: July 6, 2025 Fact Checked

Do you need to calculate the standard deviation for a list of numbers? Your TI-84 standard or TI-84 Plus graphing calculator makes it quick and easy find out how much your data varies from the mean (average). We'll show you how to use the 1-var-stats option to calculate various statistics, including the mean, sum, and both the sample (sx) and population (σx) standard deviations in one step.

How to Use the TI-84 for Standard Deviation

Open lists by pressing STAT, Edit, then ↵ Enter. Enter your values into the L1 column, then press STAT and right arrow to enter the CALC tab. Select 1-Var stats, then press 2ND and 1, then select Calculate on the menu. The standard deviation will show up next to Sx for a sample and σx for a population.

Steps

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It's in the third column of keys.^{[1]
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It's the first option on the menu. You will see columns (lists) labeled L1 through L6.^{[2]
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Note: The TI-84 allows you to enter up to six different lists of data sets.

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Clear existing data from the lists. If there's already data in any of the columns, use these steps to remove it before you continue:^{[3]
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- Use the arrow keys to navigate to L1 (the first column).
- Press ⎚ Clear.
- Press ↵ Enter.
- Repeat for other lists with data.
Press the ↵ Enter key after each value.^{[4]
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It's the second menu tab at the top of the screen.^{[6]
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Press the 2ND button and then 1 to select L1. You'll only need to do this if you have a T1-84 Plus model and don't already see "L1" next to "List."^{[7]
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- Some non-plus models may skip this screen and display your results automatically.
Tip: If you created multiple lists and want to select a different one, press the number that corresponds with that column. For example, if you want standard deviation for the values you entered in L4, press the 2ND and then 4.
The TI-84 will now display standard deviation calculations for the set of values.^{[8]
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Find the standard deviation value next to Sx or σx. These should be the 4th and 5th results in the list. You may have to scroll down to view both values.^{[9]
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- Sx shows the standard deviation for a sample, while σx shows the standard deviation for a population. The value you'll use depends on whether you used data from a sample or a full population.^{[10]
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- A lower standard deviation value means that the values in your list don't vary much from the mean, while a higher value means your data is more spread out.^{[11]
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- x̄ represents the mean, or average, of the values.
- Σx represents the sum of all values.

Community Q&A

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Question

I deleted L1, how can I revert it back?

Venatrixx

Community Answer

There is no way to revert lists. Unfortunately, you'll just have to enter the data again.

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Question

How do I find the variance with a TI-84 Plus?

Community Answer

There directly is no variance key on this calculator. However, to find the variance on a TI-84 Plus, calculate the standard deviation of your data set, then square that value.

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Question

What if the standard deviation comes up blank, with Sx showing nothing?

David Reynolds

Community Answer

If the standard deviation calculation results in a blank or undefined value, there are a few potential reasons to consider. It could be due to a lack of data points or all data points being identical, as standard deviation measures the amount of variation or dispersion in a set of values. It might also result from computational errors or incorrect application of the standard deviation formula. You should review the data set and the calculation process to identify and correct any issues.

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