Dependent variable/ Conditional Formatting Match in rstudio with the interval time

[nais90]

Hi,
Can I know how to get the data based on interval 15 minutes?
I have success to use the dplyr.. But I only get the maximum data (based on coding below)

group_by(mydf, group = cut(as.POSIXct(mydf$Day, format="%m/%d/%Y %H:%M:%S"), breaks = "15 min")) %>%
summarize_each(funs(max(.)))

How can I get the data, example column B maximum (0.04 mm/s) and column C (11 hz), looks like condition matching?

Regards,
Ikhsan