# Finding the equation of a line and predicting some points.

• Mar 16th 2010, 11:34 AM
Willo142
Finding the equation of a line and predicting some points.
Basically i have a set of data and i need too find the equation of the curve, or some other way of estimating the missing values, the data set is as follows.
Spoiler:

1951 1.365
1952 1.312
1953 1.285
1954 1.276
1955 1.182
1956 1.101
1957 0.915
1958 0.755
1959 0.581
1960 0.501
1961 0.449
1962 0.395
1963 0.357
1964 0.343
1965 0.327
1966 0.289
1967 0.265
1968 0.237
1969 0.215
1970 0.193
1971 0.176
1972 0.157
1973 0.134
1974 0.138
1975 0.116
1976 0.104
1977 0.103
1978 0.126
1979 0.112
1980 0.096
1981 0.084
1982 0.06
1983 0.063
1984 0.053
1985 0
1986 0
1987 0.067
1988 0.075
1989 0.083
1990 0.079
1991 0.089
1992 0.089
1993 0.099
1994 0.106
1995 0.097
1996 0.119
1997 0.128
1998 0.123

so far, all iv managed too do with it is calculate spearmans rank, which is
-0.96929 ideally, id like too come up with an equation with a method of working it out, and then go on too predict the missing values, can someone help me out?

• Mar 16th 2010, 01:28 PM
TKHunny
1) Why do you believe "the equation of the curve" exists?
2) I hardly can wait to see what sort of curve you believe it to be. Maybe a rational function of some sort?
3) What tools are at your disposal?
• Mar 16th 2010, 01:36 PM
Willo142
Perhaps a polynomial? second or third degree?

i have autograph and edexcell, thats about it.

All i really need is a rough curve that fits it, and how to mathematically show it, maybe a quadratic would fit it nicely
• Mar 17th 2010, 03:54 AM
CaptainBlack
Quote:

Originally Posted by Willo142
Perhaps a polynomial? second or third degree?

i have autograph and edexcell, thats about it.

All i really need is a rough curve that fits it, and how to mathematically show it, maybe a quadratic would fit it nicely

Have you plotted this data?

If it is sensible to fit this to an equation we would need to know what sort of process produced this, oterwise all you will get is nonsense.

CB