What Standard Deviation Actually Means and Why It Matters
You and your friend both average 8,000 steps a day. Same average. Same fitness goal. But your weeks look completely different. You walk about 7,800 to 8,200 steps every day. Some days are slightly higher, some slightly lower, but you are remarkably consistent. Your friend is the opposite. One day she walks 2,000 steps. The next she finishes a half marathon and records 18,000. A few days later she barely leaves the couch with 1,500, then cycles to work and reaches 14,000. ...