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❤️ 15/15

Starting With a Strange Statistic

Someone noticed that the more sunglasses a city sells, the more people get sunburned. So do sunglasses cause sunburn? That just doesn't sound right.

The truth is: on sunny days, people both buy more sunglasses and get sunburned more easily. Sunglasses and sunburn merely "go up together"—neither one caused the other.

🔆Two things showing up together are like two classmates raising their hands at the same moment—they may not even know each other; they may simply have heard the same bell ring.