The data in the file attached contains information on your firm's sales per capita, advertising expenditure per capita, and average local income.

Regress sales per capita on advertising expenditure per capita, controlling for local income as an interval variable, where intervals are <$35,000, $35,000-$44,999, $45,000-$54,999, and $55,000+, and <$35,000 is the base group.

For the remainder of the question, assume the data-generating process is

SalesperCapita_i = + ₁AdExpperCapita_i + ₂Inc35-45_i + ₃Inc45-55_i + ₄Inc55_i + U_i and that all other necessary assumptions toward establishing causality and performing inference hold.

1. Interpret the coefficients for the income intervals from your regression.
2. According to this regression, what is the effect on sales per capita when average local income increases from $35,000$44,999 to $55,000+?

Sales per Capita	Advertising Exp per Capita	Avg Local Income
$10.73	$1.25	30804
$15.56	$1.52	50680
$12.53	$1.22	31505
$14.38	$1.45	59859
$12.75	$1.58	65718
$15.04	$1.16	60858
$14.07	$1.33	63615
$15.20	$1.05	28837
$12.68	$1.63	62017
$13.64	$1.36	36390
$15.93	$1.62	63832
$13.81	$1.28	48103
$10.84	$1.30	34481
$14.41	$1.46	40696
$11.97	$1.07	41557
$14.39	$1.24	61420
$14.48	$1.50	48545
$14.64	$1.59	47667
$12.94	$1.12	57337
$12.04	$0.87	34193
$13.97	$1.30	46357
$15.22	$1.06	47852
$12.78	$1.23	31231
$13.89	$1.50	48835
$11.25	$1.28	46633
$13.31	$1.14	39840
$12.81	$1.60	55716
$12.78	$1.49	53759
$13.46	$1.20	42530
$12.96	$1.64	40563
$12.74	$1.30	40666
$13.07	$1.42	37347
$14.89	$1.62	62629
$14.26	$1.17	43950
$14.39	$1.75	64078
$13.63	$1.64	64529
$15.26	$1.05	60653
$12.68	$1.13	48035
$13.11	$1.43	49344
$15.47	$1.27	61743
$12.77	$1.25	63889
$14.47	$1.51	66324
$12.54	$1.22	41761
$13.82	$1.58	48928
$14.61	$1.69	51361
$13.60	$1.35	39107
$12.81	$1.08	51459
$14.50	$1.25	31477
$13.69	$1.45	62890
$13.47	$1.28	33064
$13.15	$1.55	64898
$13.87	$1.37	32467
$16.89	$1.36	37500
$12.23	$1.06	35976
$12.11	$1.33	54959
$10.79	$0.74	31827
$12.17	$1.63	60099
$15.86	$1.34	39278
$14.97	$1.34	65539
$12.15	$1.20	32186
$13.06	$1.24	30298
$13.89	$1.85	63625
$12.76	$1.14	36260
$13.88	$1.29	29989
$14.64	$1.42	43425
$14.72	$0.95	30718
$11.57	$1.30	45633
$12.31	$1.18	38221
$13.35	$1.10	28282
$15.75	$1.37	39117
$10.62	$1.16	28069
$13.93	$1.53	60407
$14.78	$1.45	44165
$13.91	$1.40	29470
$13.58	$1.27	63947
$13.40	$1.15	33369
$11.46	$1.31	31069
$11.11	$1.29	36320
$13.79	$1.71	44846
$14.82	$1.33	60760
$13.77	$1.45	33271
$12.47	$1.61	50649
$12.10	$1.16	40652
$13.23	$1.36	50785
$10.24	$1.63	49833
$13.77	$1.51	45068
$13.66	$1.29	42807
$15.48	$1.45	53543
$14.09	$1.56	62820
$12.30	$1.28	38859
$13.68	$1.26	40702
$14.60	$1.29	58120
$13.40	$1.21	43418
$12.20	$1.23	50274
$13.04	$1.60	45724
$14.40	$1.41	54446
$14.99	$1.34	30218
$16.38	$1.50	45554
$13.23	$1.06	28674
$13.50	$1.34	51939
$12.54	$1.53	36815
$13.38	$1.74	34599
$12.84	$1.27	32198
$12.66	$1.24	48160
$12.98	$1.35	49688
$12.39	$1.38	28442
$11.68	$1.34	31295
$14.21	$1.24	62359
$13.87	$1.46	64781
$14.38	$1.61	56258
$14.28	$1.25	45783
$13.54	$1.66	53459
$14.76	$1.43	57696
$15.47	$1.94	51462
$12.02	$1.60	35601
$12.69	$1.11	37031
$13.77	$1.72	48509
$14.75	$1.31	47326
$13.97	$1.15	36542
$13.75	$1.14	50437
$11.86	$1.40	60501
$14.45	$1.32	44381
$11.63	$1.36	54730
$13.19	$0.91	30211
$12.28	$1.38	48835
$15.56	$1.16	43918
$13.03	$1.47	31609
$9.91	$1.80	59359
$13.67	$1.87	54386
$16.18	$1.93	65989
$16.35	$1.52	41470
$13.29	$1.80	65531
$12.35	$1.42	34758
$12.55	$1.34	60157
$13.84	$1.61	60166
$12.63	$1.33	62005
$15.15	$1.30	49696
$14.70	$1.44	59502
$13.84	$1.75	59631
$12.91	$1.50	63002
$13.10	$1.72	41270
$14.52	$1.05	48152
$15.09	$1.53	52851
$12.58	$0.89	41037
$13.05	$1.30	41289
$12.75	$0.88	33472
$14.30	$1.56	53280
$12.36	$1.57	34612
$14.99	$1.17	54503
$13.91	$1.23	28147
$12.63	$1.10	29835
$12.78	$1.26	49949
$12.09	$1.36	45801
$15.33	$1.19	43928
$13.08	$1.39	62816
$11.80	$1.43	51836
$13.03	$1.64	57119
$13.62	$1.13	46663
$11.30	$1.36	42701
$14.82	$1.33	63352
$14.37	$1.41	44949
$13.57	$1.42	55423
$13.26	$1.63	48744
$13.01	$1.64	66980
$13.34	$1.65	65436
$16.12	$1.46	63973
$12.08	$1.12	42289
$12.19	$0.94	28713
$14.85	$1.98	51612
$12.66	$1.13	60954
$13.97	$1.46	55696
$13.42	$1.77	62450
$11.82	$1.23	35184
$15.62	$1.56	57265
$14.33	$1.82	61162
$12.28	$1.23	51668
$12.74	$1.21	49306
$14.81	$1.62	36963
$12.32	$0.92	39280
$11.73	$1.03	36819
$13.19	$1.59	38593
$12.17	$1.29	34541
$11.49	$1.24	48854
$12.75	$1.63	46273
$15.23	$1.17	35630
$16.74	$1.42	34580
$13.72	$1.57	66387
$13.55	$1.19	41698
$11.89	$1.19	37436
$14.86	$1.22	51526
$14.41	$1.60	34096
$12.14	$1.03	29336
$12.72	$1.64	30783
$13.33	$1.71	42985
$14.47	$1.51	55489
$14.13	$1.35	47120
$15.51	$1.54	52003
$12.97	$1.37	47426
$12.24	$1.73	64763
$11.89	$1.22	28599
$13.19	$1.66	51709
$13.90	$1.66	60675
$14.89	$1.46	32749
$15.31	$1.61	62738
$13.43	$1.50	44322
$12.93	$1.76	47166
$14.99	$1.55	55370
$14.09	$1.25	52778
$14.50	$1.67	48218
$13.72	$1.34	54228
$12.06	$1.38	54963
$12.18	$1.68	61411
$12.03	$1.02	29146
$14.04	$1.22	53944
$12.11	$1.04	54185
$12.21	$1.29	28747
$13.37	$1.26	28592
$13.71	$1.11	38826
$10.99	$1.17	59364
$13.68	$1.31	50970
$12.09	$1.51	63667
$13.32	$1.59	56936
$11.74	$1.07	38810
$12.30	$1.33	45661
$11.38	$1.04	32470
$13.12	$1.21	55511
$12.65	$1.26	37851
$16.15	$1.43	48452
$12.82	$1.25	51358
$13.97	$1.47	42424
$12.08	$1.29	30417
$13.38	$0.89	35957
$15.13	$1.57	28745
$16.14	$1.17	66184
$11.06	$1.25	51141
$11.24	$1.49	49432
$11.82	$0.83	28079
$11.72	$1.50	38102