I need to make a scatter plot for days vs age
for the f group (sex=1) and make another scatter plot for days vs age
for the m group (sex=2) using R
You can do this with the traditional R graphics functions like:
plot(age ~ days, Data[Data$sex == 1, ])
plot(age ~ days, Data[Data$sex == 2, ])
If you prefer to color the points rather than separate the plots (which might be easier to understand) you can do:
plot(age ~ days, Data, col=Data$sex)
However, this kind of plot would be especially easy (and better looking) using ggplot2:
library(ggplot2)
ggplot(Data, aes(x=days, y=age)) + geom_point() + facet_wrap(~sex)
spread splits data by column values. This is also called converting data from "long" to "wide".
I haven't tested this, but something like
spread(data, sex, age)
should get you
days 1 2
306 74 NA
455 NA 67
1000 55 NA
505 65 NA
399 NA 54
495 NA 66