Task 2: There’s been much speculation over the years about the influence of subliminal messages on records. To name a few cases, both Ozzy Osbourne and Judas Priest have been accused of putting backward masked messages on their albums that subliminally influence poor unsuspecting teenagers into doing things like blowing their heads off with shotguns. A psychologist was interested in whether backward masked messages really did have an effect. He took the master tapes of Britney Spears’ ‘Baby One More Time’ and created a second version that had the masked message ‘deliver your soul to the dark lord’ repeated in the chorus. He took this version, and the original, and played one version

(randomly) to a group of 32 people. He took the same group six months later and played them whatever version they hadn’t heard the time before.

So each person heard both the original, and the version with the masked message, but at different points in time. The psychologist measured the number of goats that were sacrificed in the week after listening to each version. It was hypothesized that the backward message would lead to more goats being sacrificed. The data are in the file DarkLord.dat.

Analyse them with a Wilcoxon signed-rank test.