Hello,

I have fitted two curves to the data. How can I tell which one is more

fitted? By eye (see plot underneath) I would say that the function

Gompertz is better than the function Holling type III; how can I give

a number to this hunch?

This is an example:

```

# functions

holling = function(a, b, x) {

y = (a * x^2) / (b^2 + x^2)

return(y)

}

gompertz = function(a, b, c, x) {

y = a * exp(-b * exp(-c * x))

return(y)

}

# data

actual <- c(8, 24, 39, 63, 89, 115, 153)

holling <- c(4.478803, 17.404533, 37.384128, 62.492663, 90.683630,

120.118174, 149.347683)

gompertz <- c(11.30771, 22.39017, 38.99516, 61.19318, 88.23403,

118.77225, 151.19849)

# plot

plot(1:length(actual), actual, lty = 1 , type = "l", lwd = 2,

xlab = "Index", ylab = "Values")

points(1:length(actual), holling, lty = 2, type = "l", col = "red")

points(1:length(actual), gompertz, lty = 3, type = "l", col = "blue")

legend("bottomright",

legend = c("Actual values", "Holling III", "Gompertz"),

lty = c(1, 2, 3), lwd = c(2, 1,1), col = c("black", "red", "blue"))

```

Thank you

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