Chapter 1: The Call at Mile Zero
RING!
Coach MoralesThe race is in two days. I have finish times, but every committee member is telling a different story.
CarmenA single fastest time is not enough. We need the of the whole group.
The Evidence
2225273133343537384142434547525661
YukiThey look like random numbers until we group them.
Detective Move
Think first: What question should the detectives answer with the data?
They decide to answer: When do most runners finish, and how spread out are the finish times?
Chapter 2: Operation Group the Data
DanteThe water crew needs time windows, not a huge list. Let's use .
Intervals chosen: 20-29, 30-39, 40-49, 50-59, 60-69 minutes.
Tally Room
20-29: 22, 25, 27
30-39: 31, 33, 34, 35, 37, 38
40-49: 41, 42, 43, 45, 47
50-59: 52, 56
60-69: 61
Chapter 3: The Histogram Rises
3
6
5
2
1
20-29
30-39
40-49
50-59
60-69
YukiThe because the intervals are connected number ranges.
Why Not a Bar Graph?
CarmenA bar graph compares categories. A histogram shows how numbers fall across intervals.
Evidence Line
Write one sentence that names the highest interval and uses the word .
Chapter 4: The Shape of the Crowd
DanteMost runners are not finishing at 22 minutes. The biggest cluster is later.
Shape clue: The data peak is at 30-39 minutes, then the bars decrease toward longer times.
Decision Board
Where should the announcer expect the busiest finish-line moment?
The busiest finish-line moment should be around 30-49 minutes, especially 30-39 minutes, because those intervals have the highest frequencies.
What About Outliers?
CarmenThe 61-minute time matters, but it should not trick us into planning the whole race around one runner.
Chapter 5: The Greenhouse Case
Coach MoralesNew case: The garden club measured plant heights. Which interval has the most plants?
4-6: 27-9: 510-12: 813-15: 416-18: 1
Yuki's Rule
YukiIf your are equal and your , the reader can scan the distribution fast.
Chapter 6: Case Closed
CarmenOur claim needs data, not vibes.
Claim: Most 5K runners finish between 30 and 49 minutes. Evidence: Those two intervals contain 11 of the 17 runners.
Final Report
Write the detectives' recommendation for the finish-line crew. Use at least one and one .
Detective Badge
DanteYou did more than draw bars. You used a histogram to make a decision.