Exercise 5: (15 pts) Install the R package/library a1r4- to get access to the data used in the book \"Applied Linear Regression, 4th edition\" by Sanford Weisberg (this book is also available online through the JH U library). This problem uses the data set UN11 from the alr4 library. The data contains several variables. We are interested mainly in the variables fertility (birth rate per 1000 females) and ppgdp (gross national product per person in US dollars). (a) Draw a scatter plot of ppgdp against fertility. Is a simple linear regression model appropriate for modeling fertility as a response variable using ppgdp as the predictor variable ? (b) Draw a scatter plot of log(ppgdp) against log(fertility). Is a simple linear regression model appro- priate now 'i' ((3) Without using the in command, estimate the least square regression line for regressing log(f ertility) on log(ppsdp)- ((1) Test the hypothesis that the relationship between the variables in part (c) is positive versus the alter native that it is negative. Give a summary of the result