It can be useful to observe trend lines, but often we'll want to understand if the trend model we've selected is statistically meaningful. Fortunately, Tableau gives us some visibility into trend models and calculations.
Simply hovering over a single trend line will reveal the formula as well as the R-Squared and P-Value for that trend line:
A P-value is a statistical concept that describes the probability that the results of assuming no relationship between values (random chance) are at least as close as results predicted by the trend model. A P-value of 5% (.05) would indicate a 5% chance of random chance describing ...
