Question

select the correct answer.
which pair of variables has a clear causal link between the two named variables?
a. the number of hats sold and the number of mittens sold in a city
b. the amount of butter and the amount of bread consumed by a family
c. the number of notebooks sold and the number of pens sold in a stationery store
d. the number of air conditioners sold per day in a city and the daily temperature
e. the number of hours a person can swim and the depth of the pool

Explanation:

To determine a causal link, we analyze each option:

• Option A: Hats and mittens sales may be correlated (e.g., winter), but no direct causal link (buying hats doesn't cause buying mittens).
• Option B: Butter and bread consumption are correlated (often eaten together) but not causal (consuming butter doesn't cause bread consumption or vice versa).
• Option C: Notebooks and pens sales are correlated (stationery items) but no direct causal link (buying notebooks doesn't cause pen sales).
• Option D: Higher daily temperature (cause) leads to more air conditioners sold (effect) – clear causal link as temperature influences demand for ACs.
• Option E: Pool depth and hours a person can swim have no causal link (depth doesn't determine swimming duration).

Answer:

D. the number of air conditioners sold per day in a city and the daily temperature