Correlation is not causation

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Quick Questions

Shade in the A or B circle for each question.

1. Ice cream sales and sunburn cases both rise in summer. What is the best conclusion?

A Hot sunny weather could be a hidden third factor affecting both

B Eating ice cream causes sunburn

2. Which statement describes a negative correlation?

A As hours of screen time go up, sleep hours go down

B As hours of study go up, test scores go up

3. A scatter plot shows a strong positive correlation between two variables. What does this tell you?

A The variables tend to rise together, but it does not prove why

B Changing one variable will definitely change the other

4. Which conclusion is worded more carefully?

A Sleeping more makes students score higher

B Students who sleep more tend to score higher, so there may be a link

5. Towns with more fire trucks sent to a fire have more fire damage. What is a likely hidden third factor?

A The colour of the fire trucks

B The size of the fire

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1Ice cream sales and shark attacks both rise in summer		AThe data shows a link between sleep and marks, but more evidence is needed
2Hours of gaming up, test scores down		BA positive correlation: two things rise together, but neither one causes the other
3A hidden third factor can explain why two variables move together		CA negative correlation: as one variable rises, the other falls
4A careful conclusion says the data shows a link, not a cause		DThis treats a correlation as a cause. Hot weather is the hidden third factor behind both.
5Sales of sunscreen rose with sales of ice cream, so sunscreen causes ice cream sales.		EHot weather -> more ice cream sales AND more swimmers at the beach
6The scatter plot slopes upward, which proves that more study time causes better marks.		F'Proves' and 'causes' are too strong. A trend shows a relationship, not the reason for it.

Definitions

correlation is not causation

Fill in the Blanks

Complete each line of code by filling in the missing parts.

=______(B2:B30,C2:C30)

Negative correlation: one rises, other _____

Hidden _____ factor may explain both

A is ______ to B, not caused by B

r near __ means strong negative correlation

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A ice <- [20, 35, 50]

B burns <- [4, 9, 14]

C r <- CORREL(ice)

Question 2

A r <- -0.8

B IF r > 0 THEN

C PRINT 'negative correlation'

D ENDIF

Question 3

A r <- 0.1

B IF ABS(r) > 0.3 THEN

C PRINT 'weak link'

D ENDIF

Question 4

A temp <- [10, 20, 30]

B heater <- [90, 50, 10]

C type <- 'positive'

D PRINT type & ' correlation'

Question 5

A r <- 0.85

B PRINT 'A causes B'

C PRINT 'Cause is unproven'

Answer Key

Correlation is not causation

Section A: Quick Questions

A — Hot sunny weather could be a hidden third factor affecting both

A — As hours of screen time go up, sleep hours go down

A — The variables tend to rise together, but it does not prove why

B — Students who sleep more tend to score higher, so there may be a link

B — The size of the fire

Section B: Match the Pairs

Ice cream sales and shark attacks both rise in summer → A positive correlation: two things rise together, but neither one causes the other

Hours of gaming up, test scores down → A negative correlation: as one variable rises, the other falls

A hidden third factor can explain why two variables move together → Hot weather -> more ice cream sales AND more swimmers at the beach

A careful conclusion says the data shows a link, not a cause → The data shows a link between sleep and marks, but more evidence is needed

Sales of sunscreen rose with sales of ice cream, so sunscreen causes ice cream sales. → This treats a correlation as a cause. Hot weather is the hidden third factor behind both.

The scatter plot slopes upward, which proves that more study time causes better marks. → 'Proves' and 'causes' are too strong. A trend shows a relationship, not the reason for it.

Section C: Definitions

correlation is not causation — Two things can rise or fall together without one causing the other. A trend shows a relationship, not the reason, so a hidden third factor may explain both.

Section D: Fill in the Blanks

=CORREL(B2:B30,C2:C30)

Negative correlation: one rises, other falls

Hidden third factor may explain both

A is linked to B, not caused by B

r near -1 means strong negative correlation

Section E: Spot the Error

C — CORREL compares two variables, so it needs two data sets. It should be r <- CORREL(ice, burns).

B — A negative correlation means r is below 0. The test should be IF r < 0 THEN.

B — A weak link means the size of r is small, so the test should be ABS(r) < 0.3. With > it would run for strong links.

C — As temperature rises, heater use falls. That is a negative correlation, so type should be 'negative'.

B — A strong r only shows a relationship. A careful conclusion says A is linked to B, not that A causes B.