search for: basestudy

Hi I need some help getting results from multiple linear models into a dataframe. Let me explain the problem. I have a dataframe with ejection fraction results measured over a number of quartiles and grouped by base_study. My dataframe (800 different base_studies) looks like > afvtprelvefs basestudy quartile ef ef_std entropy CBP0908020 1 21.6 0.53 3.27 CBP0908020 2 32.5 0.61 3.27 CBP0908020 3 30.8 0.63 3.27 CBP0908020 4 33.6 0.37 3.27 CBP0908022 1 42.4 0.52 1.80 CBP0908021...

...a problem (although I'm not certain what statistical check I could do beyond re-applying chisquared tests with only the relevant quadrants which sounds dodgy to me) the problem occurs because my data set is a couple of orders of magnitude bigger, Can anyone help? dput data is: structure(list(basestudy = structure(1:10, .Label = c("CBP06036", "CBP06095", "CBP06098", "CBP06100", "CBP06112", "CBP06118", "CBP06127", "CBP06158", "CBP06163", "CBP06166"), class = "factor"), tl = c(302L, 211L, 3...

Hi I'm trying to extract complete rows from a dataframe by group based on the maximum in a column within that group. Thus I have a dataframe: cvd_basestudy ... es_time ... _____________ study1 ... 0.3091667 study2 ... 0.3091667 study2 ... 0.2625000 study3 ... 0.3033333 study3 ... 0.2625000 __________ etc I can extract the basestudy and the max(es_time) using ddply ddply(datares_sinus_variable, .(cvd_basestudy), func...