search for: tminutes

hi there I hope you can help me I'm doing a boxplot and I'm trying to change the y-axis from seconds to minutes I do this: boxplot ( time~movement*scene, ylab = "Time (seconds)", xlab = "Condition") but seconds goes from 0 to 900 and I'm looking to change it into minutes I've been though the manuals but I don't know what you call this function so its hard