Unit 8 · Standard 6.SP.3
Mean, Median, and Mode
Key Vocabulary Level 1 support
Picture first, then the word, then a plain-language meaning. Say each word out loud.
Mean of 2, 4, 6: add them (2+4+6=12), divide by 3 → mean = 4
Mean
The average. Add all the numbers, then divide by how many there are.
Data: 1, 3, 5, 7, 9 → the middle (3rd) value is 5, so median = 5
Median
The middle number when you put them in order.
Data: 2, 3, 3, 5, 7 → 3 appears twice (most often), so mode = 3
Mode
The number that shows up most often.
Data: 10, 12, 11, 13, 50 → 50 is far from the others, so 50 is an outlier
Outlier
A number that is much bigger or smaller than the rest.
If most values cluster in the center with fewer at the ends, the distribution is symmetric
Data distribution
How the data looks: where it sits and how spread out it is.
8, 9, 10, 11 has low variability (close together); 2, 10, 25, 40 has high variability (far apart)
Variability
How spread out the numbers are.
Key Ideas & Notes
- You're the stats analyst for the school basketball team.
- Coach needs a report on the team's scoring: in the last 7 games they scored 42, 38, 55, 41, 38, 44, and 40 points.
- Which average best represents the team's typical performance?
Think About It
- What are the highest and lowest scores?
- Do any scores repeat?
- Which score seems like a typical game for this team?
My Notes
Guided Examples
Example 1
Find the mean of: 10, 14, 8, 12, 16
Solution: Sum = 10 + 14 + 8 + 12 + 16 = 60. Mean = 60 ÷ 5 = 12.
Answer: A. 12
Example 2
Find the median of: 3, 7, 2, 9, 5
Solution: Ordered: 2, 3, 5, 7, 9. The middle value is 5.
Answer: A. 5
Example 3
Find the mode of: 4, 7, 4, 9, 2, 4, 8
Solution: 4 appears three times — more than any other value. Mode = 4.
Answer: A. 4
Write About the Math The Writing Revolution
I can explain my reasoning using the words mean, median, mode, and outlier.
1. Kernel Sentence subject + verb
Model: Mean is the average. Add all the numbers, then divide by how many there are.Media es el promedio. Suma todos los números y divide entre cuántos hay.
Write a kernel sentence about mean. Use a subject and a verb.Escribe una oración base sobre media. Usa un sujeto y un verbo.
2. Sentence Expansion because · but · so
Kernel: Mean matters in mathMedia importa en matemáticas
Expand the kernel three ways. Add a reason, a contrast, and a result.
Mean matters in math because ___.Media importa en matemáticas porque ___.
Mean matters in math, but ___.Media importa en matemáticas, pero ___.
Mean matters in math, so ___.Media importa en matemáticas, entonces ___.
3. Sentence Types 4 ways to write a math idea
Tell one true fact about mean.Di un hecho verdadero sobre mean.
Mean ___.
Ask a question about mean.Haz una pregunta sobre mean.
How does ___ ?¿Cómo ___ ?
Show excitement about mean.Muestra entusiasmo sobre mean.
Wow, ___ !¡Guau, ___ !
Tell a partner what to do with mean.Dile a un compañero qué hacer con mean.
First, ___ .Primero, ___ .
4. Explain Your Reasoning use a sentence starter
The mean is ___, the median is ___.La media es ___, la mediana es ___.
They are different because ___.Son diferentes porque ___.
I would use the ___ when ___.Usaría la ___ cuando ___.
Try It
Solve on your own. Check the answer key when you are done.
1. Find the mean of: 6, 8, 10, 12, 14
- 10
- 8
- 12
- 50
2. Data set: 4, 6, 6, 8, 10, 12. What is the median?
- 7
- 6
- 8
- 7.67
Stretch Your Thinking Level 2 enrichment
Challenge task — explain your reasoning in full sentences.
A basketball player scored 15, 18, 16, 42, and 14 points in 5 games. Find the mean and median. Which better represents the player's typical game? Explain how the outlier affects each measure.
Sentence starter: Mean = ___. Median = ___. The ___ better represents a typical game because the outlier (___) pulls the ___ toward it, making it ___ than most scores. The median is not affected because ___.
Reflect — Exit Ticket
Data set: 4, 7, 10, 7, 12. What is the median?
- 7
- 8
- 10
- 4
Answer Key & Teacher Guide
- Try It 1: A. 10 — Sum = 6 + 8 + 10 + 12 + 14 = 50. Mean = 50 ÷ 5 = 10.
- Try It 2: A. 7 — With 6 values, the median is the average of the 3rd and 4th values: (6 + 8) ÷ 2 = 7.
- Exit Ticket: A. 7 — Ordered: 4, 7, 7, 10, 12. The middle (3rd) value is 7.
Writing (TWR) — what to look for
- Kernel sentence: A complete sentence needs a subject and a verb. Example: Mean is the average. Add all the numbers, then divide by how many there are.
- Expansion: because gives a reason, but shows a contrast or exception, so shows a result. Answers vary; each must keep the kernel idea and add the correct kind of detail.
- Sentence types: Statement ends with a period, question with "?", exclamation with "!", and a command starts with an action verb (a "bossy" verb).