Question

Find the trend of production by the method of a five-yearly period of moving average for the following data:

Year	Production ('000)
1979	126
1980	123
1981	117
1982	128
1983	125
1984	124
1985	130
1986	114
1987	122
1988	129
1989	118
1990	123

Answer 1

Computation of five-yearly moving averages

Year	Production ('000)	5-Yearly centred moving total	5-Yearly moving averages	5-Yearly centred moving averages
1979	126	-	-	-
1980	123	-	-	-
1981	117	619	123.8
				123.6
1982	128	617	123.4
				124.1
1983	125	624	124.8
				124.5
1984	124	621	124.2
				123.6
1985	130	615	123
				123.4
1986	114	619	123.8
				123.2
1987	122	613	122.6
				121.9
1988	129	606	121.2
1989	118	-	-	-
1990	123	-	-	-

The last column gives the trend in the production by the method of the five-yearly period of moving average.