data.test = data.frame(Date = c("16/11/2017 8:45 AM", "16/11/2017 9:00 AM",
"11/16/2017 9:15 AM", "11/16/2017 9:30 AM"), Observed = c(100, 23, 291, 30))
data.test

Date                Observed
16/11/2017 8:45 AM  100
16/11/2017 9:00 AM  23
11/16/2017 9:15 AM  291
11/16/2017 9:30 AM  30