As hypothesized , results showed significant Group ( Koru , Wait-List ) Time ( Pre , Post ) interactions for improvements in perceived stress ( F [ 1 , 76.40 ] = 4.50 , p = .037 , d = .45 ) , sleep problems ( F [ 1 , 79.49 ] = 4.71 , p = .033 , d = .52 ) , mindfulness ( F [ 1 , 79.09 ] = 26.80 , p < .001 , d = 95 ) , and self-compassion ( F [ 1 , 74.77 ] = 18.08 , p < .001 , d = .75 ) .