Two-lines test

(version 0.3)

Last updated: 2017 11 28

This app runs the u-shape test introduced by Simonsohn (2017 .pdf).

It estimates an interrupted regression, that is, a regression with two separate slopes, for the predictor hypothesized to have a u-shaped effect. If both slopes have opposite sign, and are individually statistically significant, the test rejects the null hypothesis that there is no u-shaped (nor inverted u-shaped) effect.

Start by uploading some data

If you don't have a file but want to check things out, download this datafile and then upload it.

Or, download the R Code behind the ap and run it on your computer.