Using Excel, compute seasonal indexes for the monthly data and deseasonalise the time series. Submit your excel file saved as studentID#_FINA2002. [17 marks] b) Plot the line graph showing sales data and deseasonalised sales. Comment on the graph. This graph should be included in the file named above. [4 marks] c) Discuss the reasons for seasonal adjustment of time series using credible sources (at least one journal article)

Year	Months	Sales Data, Yt ('000)	Centered 12-Month Moving Average
2010	Jan	78
	Feb	82
	Mar	122
	Apr	130
	May	146
	Jun	141
	Jul	135	127.2
	Aug	155	128.8
	Sept	141	131.5
	Oct	148	135.4
	Nov	135	139.8
	Dec	109	143.0
2011	Jan	87	146.7
	Feb	111	150.3
	Mar	157	153.5
	Apr	189	157.3
	May	192	159.5
	Jun	173	160.5
	Jul	191	163.0
	Aug	187	165.1
	Sept	186	165.4
	Oct	193	164.9
	Nov	143	163.8
	Dec	125	162.8
2012	Jan	131	161.5
	Feb	117	159.2
	Mar	158	155.7
	Apr	177	151.0
	May	176	146.9
	Jun	165	143.5
	Jul	170	139.2
	Aug	152	135.6
	Sept	136	132.8
	Oct	130	128.5
	Nov	108	123.0
	Dec	79	116.3
2013	Jan	74	109.1
	Feb	88	103.6
	Mar	118	100.2
	Apr	114	97.3
	May	109	94.7
	Jun	71	93.7
	Jul	90	93.6
	Aug	101	93.2
	Sept	104	93.2
	Oct	94	94.2
	Nov	81	96.9
	Dec	81	102.3
2014	Jan	71	107.7
	Feb	81	112.6
	Mar	125	116.9
	Apr	130	121.0
	May	159	125.8
	Jun	149	129.7
	Jul	142	133.9
	Aug	167	138.2
	Sept	141	141.7
	Oct	157	145.0
	Nov	131	149.1
	Dec	126	155.1
2015	Jan	126	161.9
	Feb	129	166.9
	Mar	162	171.1
	Apr	173	175.4
	May	214	179.9
	Jun	238	183.5
	Jul	216	185.3
	Aug	212	186.5
	Sept	197	187.5
	Oct	205	188.6
	Nov	191	188.3
	Dec	152	186.5
2016	Jan	143	183.7
	Feb	141	179.3
	Mar	175	174.2
	Apr	185	168.6
	May	195	162.3
	Jun	214	156.5
	Jul	173	151.8
	Aug	149	147.5
	Sept	137	142.3
	Oct	131	135.9
	Nov	114	128.3
	Dec	91	118.8
2017	Jan	91	109.8
	Feb	88	104.0
	Mar	104	100.3
	Apr	102	97.7
	May	96	95.8
	Jun	85	94.8
	Jul	86	94.5
	Aug	97	94.7
	Sept	101	95.8
	Oct	103	98.1
	Nov	96	102.0
	Dec	87	107.4
2018	Jan	87	113.6
	Feb	97	119.7
	Mar	121	125.8
	Apr	141	132.2
	May	151	138.3
	Jun	158	143.4
	Jul	162	147.7
	Aug	167	152.3
	Sept	178	157.9
	Oct	180	164.6
	Nov	166	172.0
	Dec	139	179.5
2019	Jan	138	186.9
	Feb	156	194.5
	Mar	196	202.4
	Apr	228	210.3
	May	242	217.3
	Jun	245	222.8
	Jul	253
	Aug	260
	Sept	274
	Oct	273
	Nov	240
	Dec	198