A TI-84 shows the mean as x̄ and the median as Med on the 1-Var Stats screen, but it has no mode function. To find the mode, sort the list with SortA( and look for the value that repeats most. The calculator above finds all three at once and lists every mode when there is a tie.
How to find the mean and median on a TI-84
1-Var Stats gives you the mean and the median in one run. It sits in the STAT menu along with the rest of the TI-84 statistics calculators.
- Press STAT, then 1 to open Edit.
- Clear L1 if it has old numbers: highlight the L1 heading, press CLEAR, then ENTER.
- Type each value into L1 and press ENTER after it.
- Press 2nd, then MODE to quit to the home screen.
- Press STAT, press the right arrow to CALC, and press 1 for 1-Var Stats.
- Set List to L1 if asked, then select Calculate.
- Read x̄ at the top for the mean. Press the down arrow until you reach Med for the median.
For just one number, use the LIST menu instead. Press 2nd STAT, move right to MATH, and choose 3 for mean( or 4 for median(. Type L1, close the parenthesis, and press ENTER.
Why the TI-84 has no mode function
The TI-84 has no mode command because a data set can have no mode, one mode, or several. A single number on the screen cannot show all three cases, so Texas Instruments left it out of 1-Var Stats.
You can still find the mode in about ten seconds by sorting the list. Equal values end up next to each other, which makes repeats easy to spot.
- Press STAT, then 2 for SortA(.
- Press 2nd 1 to paste L1, close the parenthesis, and press ENTER.
- Press STAT, then 1 to view the sorted list.
- Scroll down and find the value that appears most often.
Sorting changes the order of L1. If the order matters, for example when L2 holds matching data, sort a copy instead. You can copy the list with 2nd 1, STO→, 2nd 3 to store L1 in L3.
Reading the 1-Var Stats output screen
1-Var Stats fills more than one screen. The first part shows the mean and spread, and the median is further down with the quartiles.
| Line | What it tells you |
|---|---|
| x̄ | Mean, the sum divided by the count |
| Σx and Σx² | Sum of the values and sum of their squares |
| Sx and σx | Sample and population standard deviation |
| n | How many values the list holds |
| minX and maxX | Smallest and largest value |
| Q1 and Q3 | First and third quartile |
| Med | Median, the middle value of the sorted list |
minX, Q1, Med, Q3, and maxX together make the five number summary used for box plots. For more on Sx and σx, see the standard deviation calculator.
Worked example
Take the number of texts eight friends sent before lunch: 3, 7, 7, 2, 9, 7, 4, and 2. Sorted, the list reads 2, 2, 3, 4, 7, 7, 7, 9.
| Measure | How to get it | Value |
|---|---|---|
| Mean (x̄) | 41 ÷ 8 | 5.125 |
| Median (Med) | Average of the 4th and 5th values, 4 and 7 | 5.5 |
| Mode | 7 appears three times | 7 |
| Q1 | Median of 2, 2, 3, 4 | 2.5 |
| Q3 | Median of 7, 7, 7, 9 | 7 |
With an even count of 8, there is no single middle value. The TI-84 averages the two middle values, 4 and 7, to get a median of 5.5.
Notice that the mean of 5.125 sits below the median. The two low values of 2 pull the mean down more than they move the median. When the mean and median differ a lot, the data is skewed.
Common mistakes
- Reading Sx as the mean. The mean is always the x̄ line at the top of the screen.
- Stopping at the first screen. Med and the quartiles are below, so press the down arrow.
- Forgetting to sort before hunting for the mode. Repeats in an unsorted list are easy to miss.
- Calling a data set with no repeats "mode 0". If no value repeats, there is no mode.
- Leaving old numbers at the bottom of L1. If n is larger than your count, clear the list and start over, or see how to reset a TI-84 to clear every list at once.
FAQ
How do you find the mode on a TI-84?
Sort the list, then look for the value that repeats most. Press STAT, 2 for SortA(, then 2nd 1 for L1, close the parenthesis, and press ENTER. Open STAT, Edit to see the sorted list. Repeated values now sit together, so the mode is easy to count.
Where is the median on 1-Var Stats?
The median is the Med line, below the first screen of results. After running 1-Var Stats, press the down arrow until you pass minX and Q1. Med appears next, followed by Q3 and maxX. On a TI-84 Plus CE you may see it without scrolling.
What does x-bar mean on a TI-84?
X-bar, written x̄, is the mean of your data. The TI-84 adds every value in the list and divides by n, the number of values. It is the first line on the 1-Var Stats screen. You can paste it into a formula from VARS, 5 for Statistics, 2.
How do you enter data into L1 on a TI-84?
Press STAT, then 1 for Edit. The cursor starts in the L1 column. Type the first value and press ENTER, and the cursor drops to the next row. Repeat for every value. Press 2nd MODE when you finish to return to the home screen.
Can a TI-84 find the mode automatically?
Not with a built-in command. No menu on the TI-84 returns the mode, and 1-Var Stats skips it. Sorting the list is the fastest manual method. Some students load a short program to do it, but most teachers expect you to sort and count.
What is Med on a TI-84?
Med is the median, the middle value of your data once it is sorted. With an odd count it is the center value. With an even count it is the average of the two center values. It appears on the 1-Var Stats screen between Q1 and Q3.