I totally understand why the data might look scattered at first glance.
Key Insight: negative correlation does NOT mean a perfect downward line — it just means that, overall, as one variable increases, the other tends to decrease.Let me sort the data by self-check unlimited lanes so the pattern becomes clear:
0 unlimited lanes: Store D (
50.5), Store G (
38.8), Store I (
56.7) — average age around
48.74 unlimited lanes: Store A (
34.5), Store C (
32.0), Store E (
42.5) — average age around
36.36 unlimited lanes: Store B (
28.4), Store F (
34.6) — average age around
31.58 unlimited lanes: Store H (
29.9) — age
29.9Now look at the group averages as unlimited lanes increase:
48.7 →
36.3 →
31.5 →
29.9. That is a
clear downward trend!Yes, there is scatter within each group — for example, at
0 lanes, ages range from
38.8 to
56.7. But
correlation measures the overall tendency, not perfection. Think of it this way: if you plotted all
9 points on a graph with unlimited lanes on the x-axis and age on the y-axis, the
best-fit line would clearly slope downward. That is what makes it a
negative correlation.
The GMAT trick here is that you do not need to calculate a
correlation coefficient. You just need to observe: stores with MORE unlimited lanes consistently tend to have LOWER average customer ages, and stores with FEWER unlimited lanes tend to have HIGHER ages. Every single store with
6 or
8 unlimited lanes has a below-average customer age (under
38.66), while every store with
0 unlimited lanes has an above-average or near-average customer age. That overall pattern is enough to confirm a
negative correlation.
Answer: True, True, False