Generate noisy data around a perfectly flat reality and watch alarming dips appear out of nothing. The fewer days you look at, the wilder the story. More data, calmer story.
Interactive — signal vs. noisehit ‘new data’
the datathe truththe trend you’d draw
same reality, fresh noise
We're crashing. that's the noise talking.
What it looks like
-0.9%/day
the slope through the dots
What is really going on
0%/day
flat — you set it
noise, not signalThis slope sits within the noise (t = -1.0) — it could easily be nothing.
Reality is flat. Every slope here is invented by 10 noisy days — hit “new data” and it lurches, up one run, down the next. Add days, and the fake trend collapses toward zero.