1. (20 points) Run a regression of Walmart Sales (y) on both CPI and Retail Price Index.
   1. Is this a good model? Are any points odd? What is interesting about those odd points?

Sales ($B)	CPI	Retail Price Index
14.764	552.7	301337
23.106	552.1	357704
12.131	554.9	281463
13.628	557.9	282445
16.722	561.5	319107
13.98	563.2	315278
14.388	566.4	328499
18.111	568.2	321151
13.764	567.5	328025
14.296	567.6	326280
17.169	568.7	313444
13.915	571.9	319639
15.739	572.2	324067
26.177	570.1	386918
13.17	571.2	293027
15.139	574.5	294892
18.683	579	338969
14.829	582.9	335626
15.697	582.4	345400
20.23	582.6	351068
15.26	585.2	351887
15.709	588.2	355897
18.618	595.4	333652
15.397	596.7	336662
17.384	592	344441
27.92	589.4	406510
14.555	593.9	322222
18.684	595.2	318184
16.639	598.6	366989
20.17	603.5	357334
16.901	606.5	380085
21.47	607.8	373279
16.542	609.6	368611
16.98	610.9	382600
20.091	607.9	352686
16.583	604.6	354740
18.761	603.6	363468
28.795	604.5	424946
20.473	606.348	332797