How to Do Statistics on a TI-84 Calculator: Mean, Median, Standard Deviation & More

Whether you are taking AP Statistics, a college stats course, or just trying to survive your first data analysis assignment, the TI 84 calculator is one of the most powerful tools you have. The STAT menu alone can calculate mean, median, standard deviation, quartiles, linear regression, and more in seconds if you know the right button sequence.

This guide walks you through every major statistics function on the TI-84, step by step. No experience needed.

How do you do statistics on a TI-84?

Press [STAT] → [ENTER] to open the list editor and enter your data into L1. Then press [STAT] → arrow right to CALC → press [1] for 1-Var Stats → press [ENTER]. The calculator instantly displays the mean (x̄), standard deviation (Sx and σx), median (Med), quartiles (Q1, Q3), minimum, and maximum of your data set.

Don't have a physical TI-84? Use our free TI-84 calculator online — no download needed, works on any device.

What You Will Learn in This Guide

• How to enter data into the TI-84 STAT lists
• How to find the mean (average)
• How to find the median
• How to find the standard deviation (both sample and population)
• How to find the 5 number summary (min, Q1, median, Q3, max)
• How to calculate linear regression
• Common mistakes and how to fix them
• How to find the variance

Step 1: Enter Your Data Into the TI-84

Before you can calculate anything, you need to enter your data into a list. The TI-84 stores data in lists named L1, L2, L3, and so on.

Button sequence:

1. Press [STAT]

2. Press [ENTER] (this selects "1: Edit")

3. You will see columns labeled L1, L2, L3

4. Use the arrow keys to move your cursor into the L1 column

5. Type your first number and press [ENTER]

6. Continue entering each number, pressing [ENTER] after each one

7. When done, press [2nd] then [QUIT] to return to the home screen

Example data set we will use throughout this guide:

`85, 92, 78, 95, 88, 76, 91, 84, 89, 90`

Tip: If your L1 already has old data in it, clear it first. Move your cursor up to highlight the L1 heading (not any number below it the heading itself) and press [CLEAR] then [ENTER]. This wipes the entire list without deleting the list itself.

Step 2: How to Find the Mean (Average) on a TI-84

The mean is the first result that appears when you run 1-Var Stats.

Button sequence:

1. Press [STAT]

2. Arrow right to CALC

3. Press [1] to select 1-Var Stats

4. On newer TI-84 models: make sure List says L1 and FreqList is empty → arrow down to Calculate → press [ENTER]

5. On older models: just press [ENTER] after selecting 1-Var Stats

What you will see:

The screen shows x̄ this is your mean (average).

For our example data set: **x̄ = 86.8**

This means the average score in our data set is 86.8.

Step 3: How to Find the Median on a TI-84

The median appears further down the 1-Var Stats results screen you need to scroll down to find it.

After running 1-Var Stats (Step 2 above):

1. Use the down arrow key to scroll through the results

2. Scroll past: x̄, Σx, Σx², Sx, σx, n, minX, Q1

3. You will see Med this is your median

For our example data set: Med = 88.5

The median is the middle value when data is arranged in order. The TI-84 calculates it automatically you do not need to sort the data yourself first.

Step 4: How to Find Standard Deviation on a TI-84

Standard deviation appears right in the main 1 Var Stats results you will see two versions:

| Symbol | What it means | When to use it |

|--------|--------------|----------------|

| Sx | Sample standard deviation | When your data is a sample from a larger population (most common in class) |

| σx | Population standard deviation | When your data IS the entire population |

How to read the results:

After running 1 Var Stats, the third and fourth lines show:

- Sx = sample standard deviation

- σx = population standard deviation

For our example data set:

- Sx = 6.14 (sample standard deviation)

- σx = 5.83 (population standard deviation)

Which one should you use?

In most AP Statistics and college stats courses, you will use Sx (sample standard deviation) because you are almost always working with a sample, not an entire population. If your teacher or textbook specifies "population standard deviation," use σx.

Step 5: How to Find the 5 Number Summary on a TI-84

The 5 number summary consists of: Minimum, Q1, Median, Q3, Maximum. The TI-84 calculates all five at once inside the 1 Var Stats results.

After running 1-Var Stats, scroll down and you will see:

| Statistic | Symbol on TI-84 | Our example |

| Minimum | minX | 76 |

| First Quartile | Q1 | 83.25 |

| Median | Med | 88.5 |

| Third Quartile | Q3 | 91.25 |

| Maximum | maxX | 95 |

This is everything you need to draw a box and whisker plot or describe the spread of your data set.

This is everything you need to draw a box-and-whisker plot or describe the spread of your data set.

For more TI-84 tips and shortcuts, see our Top 10 TI-84 Tricks guide.

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Step 6: How to Find the Variance on a TI-84

The TI-84 does not display variance directly, but you can calculate it in one extra step since variance = standard deviation².

Button sequence:

1. Run 1-Var Stats (Step 2) to calculate the statistics
2. Go back to the home screen: press [2nd] then [QUIT]
3. Press [VARS]
4. Arrow right to Statistics
5. Press [ENTER] to select Sx (or scroll to σx if you need population variance)
6. Press [x²] to square it
7. Press [ENTER]

The result is your variance.

For our example: Sx = 6.14, so variance = 6.14² = 37.7

Alternatively: Simply take the Sx value shown on screen and square it on the home screen manually.

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Step 7: How to Calculate Linear Regression (LinReg) on a TI-84

Linear regression finds the best-fit line (y = ax + b) through a set of data points. This is one of the most tested skills in AP Statistics.

You will need two lists: x-values in L1, y-values in L2.

Button sequence:

1. Press [STAT] → [ENTER] to open the list editor
2. Enter your x-values into L1
3. Arrow right to L2 and enter your y-values
4. Press [2nd] then [QUIT]
5. Press [STAT] → arrow right to CALC
6. Press [4] to select LinReg(ax+b)
7. Make sure Xlist: L1 and Ylist: L2 are set
8. Arrow down to Calculate → press [ENTER]

What you will see:

• a = slope of the regression line
• b = y-intercept
• r = correlation coefficient (how strong the linear relationship is)
• r² = coefficient of determination

Why is r not showing? If you do not see the r and r² values, you need to turn on DiagnosticsOn:

1. Press [2nd] then [0] to open the Catalog
2. Scroll down to DiagnosticOn
3. Press [ENTER] twice

Now re-run LinReg and you will see r and r².

For a step-by-step guide to graphing your regression line, visit our how to graph on a TI-84 guide.

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Step 8: How to Use 2-Var Stats on a TI-84

2-Var Stats calculates statistics for two variables simultaneously — useful for bivariate data analysis.

Button sequence:

1. Enter x-values in L1, y-values in L2
2. Press [STAT] → CALC → [2] for 2-Var Stats
3. Set Xlist: L1 and Ylist: L2 → Calculate → [ENTER]

You will see the mean, standard deviation, and sum for both variables, plus the sum of products (Σxy) which is used in correlation calculations.

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Step 9: How to Make a Histogram on a TI-84

Histograms visualize the distribution of your data — a key part of AP Statistics.

Button sequence:

1. Enter your data into L1
2. Press [2nd] then [Y=] to open STAT PLOTS
3. Press [1] to select Plot 1
4. Press [ENTER] to turn it On
5. Arrow down to Type: and select the histogram icon (3rd option)
6. Make sure Xlist is set to L1
7. Press [ZOOM] then [9] (ZoomStat) to auto-fit the histogram
8. Press [GRAPH]

Your histogram will appear. Press [TRACE] and use the arrow keys to see the frequency of each bar.

Tip: If you get an ERR: INVALID DIM error, it means a stat plot is turned on that conflicts with your graph. See our TI-84 troubleshooting guide for the fix.

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Common Mistakes When Doing Statistics on a TI-84

Mistake 1: Not clearing old data from L1 If L1 has leftover numbers from a previous calculation, your statistics will be wrong. Always clear the list first (highlight the L1 heading → CLEAR → ENTER).

Mistake 2: Using σx instead of Sx In most classroom situations, Sx (sample standard deviation) is the correct one to report. Using σx gives a slightly different answer and may lose you marks.

Mistake 3: Forgetting to turn on DiagnosticOn for r values If you run LinReg and don’t see r or r², you haven’t enabled diagnostics. Follow Step 7 above to turn it on.

Mistake 4: Entering frequency data without using FreqList If your data is in grouped frequency form (e.g., “score 85 appeared 5 times”), you need to put the frequencies in L2 and set FreqList: L2 when running 1-Var Stats. If you ignore this, your mean and standard deviation will be wrong.

Mistake 5: L1 not selected when running 1-Var Stats On newer TI-84 Plus CE models, 1-Var Stats shows a setup screen asking which list to use. Make sure it says List: L1 before pressing Calculate.