when to use r to determine correlation what package is used to test for xy correlation what package can the best of xy relationships be used how to calculate the xy correlation in an r model? how long is y in the r model how to test correlations in r how many quarters are x and y in r when can you test correlation how to test for xy correlation r how to calculate correlations how to calculate correlation using foreach how to time efficient correlate what is the best correlation in r how to test correlation in r how to test for correlation which package can time efficiently measure correlations? when does the best time efficient correlation occur which package can test correlation which package is most apt to measure correlation how many quarters in a z-series?