You have been asked to select a 10% sample of firms from the sampling frame below

OUTPUT ($'0000)	OUTPUT ($'0000)	OUTPUT ($'0000)	OUTPUT ($'0000)	OUTPUT ($'0000)
0 1163	20 1072	40 1257	60 1300	80 1034
1 10	21 7	41 29	61 39	81 55
2 57	22 92	42 84	62 73	82 66
3 147	23 105	43 97	63 161	83 165
4 205	24 157	44 265	64 275	84 301
5 163	25 214	45 187	65 170	85 161
6 1359	26 1440	46 1872	66 1598	86 1341
7 330	27 390	47 454	67 378	87 431
8 2097	28 1935	48 1822	68 1634	88 1756
9 1059	29 998	49 1091	69 1101	89 907
10 1037	30 1298	50 1251	70 1070	90 1158
11 59	31 10	51 9	71 37	91 27
12 68	32 70	52 93	72 88	92 66
13 166	33 159	53 103	73 102	93 147
14 302	34 276	54 264	74 157	94 203
15 161	35 215	55 189	75 168	95 163
16 1298	36 1450	56 1862	76 1602	96 1339
17 329	37 387	57 449	77 381	97 429
18 2103	38 1934	58 1799	78 1598	98 1760
19 1061	39 1000	59 1089	79 1099	99 898

Required: a) Select a 10% systematic sample and mark those firms selected for the sample on the sampling frame. b) Calculate the average (mean) annual output in tens of thousands of dollars over the past year for each of the samples selected. c) Given that the true average annual output is $6,608, 900, why does systematic sampling provide such a poor estimate of the annual output in this case?