PSYC 2021 - Statistical Methods I Lab Exercise 3: Correlation As always, solve the following questions using R, and for practice also solve some or all of them "by hand" 1. Below are the depression (DEP) and posttraumatic stress (PTS) scores of 15 soldiers who served in Ukraine DEP: 22, 18, 15, 51, 38, 32, 37, 11, 9, 19, 34, 17, 11, 27, 30 PTS: 45, 32, 24, 67, 74, 56, 82, 22, 22, 65, 66, 35, 17, 34, 52 a) create a scatterplot of the relationship between DEP and PTS b) convert the DEP and PTS scores to standard (z) scores and calculate the correlation using the formula r = [ ZxZy / (N-1) c) calculate and interpret the correlation between Depression and PTS using a built in R function 2. Make up two variables (x, y) of 12 cases each that are negatively related. Use a scatterplot and correlation coefficient to verify that you have created the requested relationship