"How tall am I?" has one answer. "How tall are the students in my class?" has many.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
Only the second kind needs statistics.
Statistical question is one you expect to have different answers for different cases.
Why summaries exist
Thirty different heights are hard to hold in mind, so one number stands in for the set.
Variability is the point
If every answer were identical there would be nothing to summarise and no statistics.
A statistical question expects variation
"How tall am I?" has one answer. "How tall are the students in this class?" has many, and they vary. Statistics exists because of that variability — a question with a single answer needs measurement, not statistics.
Telling them apart
"What is the temperature right now?" is not statistical. "What are the daily temperatures here in June?" is, because the answers spread out. The test is whether you expect different answers, not whether the question is hard.
The answer is a distribution
A statistical question is answered by a set of values with a shape, a centre and a spread — not by one number. Reporting only the average discards the variability that made the question statistical in the first place.
Asking a good one
A good statistical question specifies who is being measured, what is being measured, and how. "How long do students take to get to school?" is better than "How long is the journey?" because it says whose journeys and leaves less to interpretation.
Step 2: Try It Yourself
Tap and try it out.
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Books read last month14 things were measured in all.
The tallest column is at 3, with 5 marks.
Step 3: Watch an Example
One step at a time.
Watch Leo Sort Two Questions
Leo is given "How old is my teacher?" and "How old are the teachers here?".
- Step 1
The first has exactly one answer, whoever asks it.
Step 4: Your Turn
Practice makes it stick.
Which One
Problem 1 of 2
Is "How many pets does each student in my class have?" statistical?
The Other One
Problem 2 of 2
Is "How many days are in July?" statistical?
Statistical or Not?
1 of 4
Is "How tall is the tallest tree in the park?" statistical?
2 of 4
Is "How tall are the trees in the park?" statistical?
3 of 4
Is "What time does school start?" statistical?
4 of 4
Is "How long does each student take to get to school?" statistical?
Step 5: Quick Check
Show what you know.
Question 1 of 2
Is "How many siblings does each child in the club have?" statistical?
Question 2 of 2
What makes a question statistical?
What You Learned
- A statistical question expects different answers.
- A question with one answer needs no statistics.
- Summaries exist because the answers vary.