Consider the daily simple returns of Caterpillar (CAT) stock, CRSP value-weighted index (VW), CRSP equal-weighted index (EW), and the S&P composite index (SP) from January 3 , 2007, to December 31, 2016. Returns of the three indexes include dividends. The data are in the file d-cat0716-3dx.txt and the columns show promo of CAT, date, VOL, RET, vwretd, ewretd, and sprtrn, respectively, with the last four columns showing the simple returns. In the file, VOL and RET denote trading volume and return, respectively. (a) Compute the sample mean, standard deviation, skewness, excess kurtosis, minimum, and maximum of each simple return series. (b) Obtain the empirical density function of the simple returns of Caterpillar stock. Are the daily simple returns normally distributed? Perform a normality test to justify your answer . (c) Transform the simple returns to log returns. Compute the sample mean, standard deviation , skewness, excess kurtosis, minimum, and maximum of each log return series. (d) Test the null hypothesis that the mean of the log-returns of Caterpillar stock is zero. Do the same test for S&P composite index. (e) Obtain the empirical density plot of the daily log-returns of Caterpillar stock and the equal-weighted index. Where to find the data: learn how to import the data from a web page. https://faculty.chicagobooth.edu/ruey.tsay/teaching/bs41202/sp2017/d-cat0716-3dx.txt