3. Use R to complete the following problem: Consider the following sales data for January 2002 through December 2003. Date Sales Date Sales Jan-02 1,158 Jan-03 1,186 Feb-02 1,097 Feb-03 1,110 Mar-02 1,297 Mar-03 1,337 Apr-02 1,539 Apr-03 1,490 May-02 1,691 May-03 1,743 Jun-02 1,605 Jun-03 1,665 Jul-02 1,560 Jul-03 1,616 Aug-02 1,471 Aug-03 1,537 Sep-02 1,325 Sep-03 1,485 Oct-02 1,406 Oct-03 1,498 Nov-02 1,400 Nov-03 1,432 Dec-02 1,460 Dec-03 1,511 (a) Plot the series. What can you learn by examining this plot? (b) Calculate and display the first 8 autocorrelations for the series. What do the ACF and PACF suggest about the series? (c) Suggest a possible set of differencing to use with the series