为什么 Tableau 中有三个趋势线

Question

In Tableau when I go to Analysis > Trend Lines > Show Trend Lines, why does it show 3 trend lines?

What does this mean?

Or can you tell me to google to figure this out? I'm stumped ???

Answer 1

The lines above and below are confidence bands : http://onlinehelp.tableau.com/current/pro/desktop/en-us/trendlines_add.html

Tableau confidence bands show upper and lower 95% confidence lines by default when you add trend lines.

You can turn them off by clicking "Show Confidence Bands" in the dialog.

Answer 2

The upper and lower lines in tableau linear trend lines are actually the confidence lines that shows the variation of the trend along the whole graph.Means, closer the confidence lines to the main trend line, means more closer is the trend line towards the main graph or plot. So, these are actually the helping lines.