> air_mess <- sample_frac(airquality, 1)
> head(air_mess)
    Ozone Solar.R Wind Temp Month Day
21      1       8  9.7   59     5  21
42     NA     259 10.9   93     6  11
151    14     191 14.3   75     9  28
108    22      71 10.3   77     8  16
8      19      99 13.8   59     5   8
104    44     192 11.5   86     8  12