Practice Set · Part 1
Describe the Data Using the Median
Pick up where we left off
Where we left off
Our goal: With my small group, I can find the median of a data set and use it to describe what is typical — one step at a time, with support.
The big idea: The median is the middle value once the data is in order. With an even count, it is the mean of the two middle values — and it is the measure that an unusually high or low value cannot drag around.
Model to copy — Watch me find the median
- My data set: 2, 4, 4, 6, 9 — five values, already in order. Ordering first is what makes a middle exist at all.
- With 5 values, the middle is the 3rd one. Counting in from both ends: 2 and 9 pair off, 4 and 6 pair off, and 4 is left alone.
- So the median is 4. Half the values sit at or below it and half at or above it.
- Now an even set: 2, 4, 6, 9. There is no single middle, so I take the mean of the two middle values: (4 + 6) ÷ 2 = 5. The median is 5, even though 5 is not in the data.
Start here
You did these with your group. Now do them on your own — the model above is yours to copy.
- 1
Same stepsFinish what the group started. Use the model above, step for step.
Let's do one together: New data set, out of order: 13, 3, 7, 10, 7. Put it in order first. In order: 3, 7, 7, 10, 13. Five values, so the middle is the 3rd. The median is 7. Say what it means: a typical value in this set is about 7. Now change the 13 to 130. Does the median move? It does not — still 7. That resistance is exactly why the median is used.My first step is ___ , because the problem asks for ___ .
Show your work - 2
Warm restartA histogram bar for the interval 10–19 has a height of 6. How many data values fall in that interval?
- A6
- B10
- C19
- D16
- 3
Warm restartA histogram uses the intervals 0–9, 10–19 and 20–29. What is the width of each interval?
- A10
- B9
- C3
- D29
- 4
Warm restartA histogram has bar heights 3, 7, 5 and 2. How many data values are in the whole set?
- A17
- B7
- C4
- D15
Practice Set · Part 2
Describe the Data Using the Median
Keep going
You answered these out loud. Now write them.
Answer, then say how you know — the reason is the part that counts.
- 5
Think it throughThe teacher said 'most students scored around 87.' Which measure is that?
- AThe mean (average)
- BThe mode
- CThe median
- DThe range
Why is that the answer?
I chose ___ because ___ .
- 6
Think it throughThe student said 'the most common score was 92.' Which measure is that?
- AThe mode
- BThe mean
- CThe median
- DThe range
How do you know?
I chose ___ because ___ .
- 7
Think it throughWhat is the median of the 10 scores?
- A88
- B87
- C92
- D86.6
Explain your thinking.
I chose ___ because ___ .
- 8
Back to the modelThe mean (43) is higher than the median (41). Why? Which better represents a typical game?
The mean is higher than the median because the high score of ___ pulls the mean ___. The ___ better represents a typical game because ___.
Practice Set · Part 3
Describe the Data Using the Median
Words and reasoning
Word bank · Banco de palabras
Use the words
Fill each blank with a word from the bank.
- When one value sits far from the rest, describe the typical value with the ___.
- The middle value of a data set when the numbers are in order is the ___.
- The value that appears most often in a data set is the ___.
- A value that is much larger or smaller than the rest of the data is an ___.
Explain the thinking
- 9
Find the mistakeAnother student made this exact mistake in this lesson. Explain why it is wrong, then write what they should have done.
The mistake: A common mistake in Mean, Median, and Mode is finding the median without ordering the data first — students pick the middle number straight from the list as given (for 9, 4, 7, 2, 6 they say the median is 7, the middle position in that original order) instead of sorting least to greatest (2, 4, 6, 7, 9) and finding the true middle value, 6. - 10
Say moreAfter ordering the scores on the number line, how do you find the median, and how is it different from the mean you calculated?
To find the median, I first ___ the scores, then pick the ___.
- 11
Change one numberGo back to Part 1 and pick one problem you already solved. Change one number in it, then solve your new version. Show every step.
If ___ changed to ___ , then ___ .
Show your work
Practice Set · Part 4
Describe the Data Using the Median
Show what you know
Last check
These two come from Lesson 2.2. If they are shaky, that is the lesson to revisit — not this one.
- 12
Show what you knowQuick check — you've got this: Data set: 4, 7, 10, 7, 12. What is the median, and what does it tell you?
- A7 — a typical value in this set is about 7
- B10 — it is the middle number as the list is written
- C8 — it is the average of all five values
- D12 — it is the largest value
Explain your choice.
I know it is ___ because ___ .
- 13
From Lesson 2.2Quick check — you've got this: A histogram of player heights shows: 60–63 in: 2, 64–67 in: 7, 68–71 in: 9, 72–75 in: 4. Which interval has the most players?
- A72–75 inches
- B60–63 inches
- C68–71 inches
- D64–67 inches
- 14
From Lesson 2.2Does the histogram support the coach's claim?
- AYes — 18 of 23 players cluster in the middle intervals
- BNo — most players take 0–2 shots
- CNo — the data is skewed right
- DYou cannot tell from a histogram
Be honest — this tells your teacher what to do next
| I can… | Not yet | Getting there | Got it |
|---|---|---|---|
| I can find the median of a data set and use it to describe what is typical — one step at a time, with support. | |||
| I can explain why it works: The median is the middle value once the data is in order. With an even count… | |||
| I can talk through each step out loud using a sentence frame and the lesson's key words. |
One question I want to ask my group next time