uintercept =~ 1*use1 + 1*use2 + 1*use3 + 1*use4
uslope =~ 0*use1 + 1*use2 + 2*use3 + 3*use4
uintercept ~ ease
uslope ~ ease
#
pintercept =~ 1*prof1 + 1*prof2 + 1*prof3 + 1*prof4
pslope =~ 0*prof1 + 1*prof2 + 2*prof3 + 3*prof4
pintercept ~ ease
pslope ~ ease
#
uslope ~ NA*1
uintercept ~ NA*1
pintercept ~ NA*1
pslope ~ NA*1
#
use1 ~ 0*1
use2 ~ 0*1
use3 ~ 0*1
use4 ~ 0*1
#
prof1 ~ 0*1
prof2 ~ 0*1
prof3 ~ 0*1
prof4 ~ 0*1
