EXAMPLE OF HOW TO USE R FOR EXPONENTIAL DISTRIBUTION & EXPONENTIAL REGRESSION

Hi,

Please also include R-help in your replies - I can't provide
one-on-one tutorials.

Without knowing where you got your sample code, it's hard to help. But
what are you trying to do?

It doesn't have to be that complicated:

x <- 1:10
y <- c(0.00, 0.00,0.0033,0.0009,0.0025,0.0653,0.1142,0.2872,0,1 )
plot(x, y, pch=20)

# basic straight line of fit
fit <- glm(y~x)

abline(fit, col="blue", lwd=2)
exp.lm <- lm(y ~ exp(x))
lines(1:10, predict(exp.lm, newdata=data.frame(x=1:10)))


On Tue, Nov 27, 2018 at 9:34 AM Tolulope Adeagbo
<tolulopeadeagbo at gmail.com> wrote:

Hello,

So I found this example online but there seems to be an issue with the

"Start" points. the result is giving somewhat a straight line

# get underlying plot
x <- 1:10
y <- c(0.00, 0.00,0.0033,0.0009,0.0025,0.0653,0.1142,0.2872,0,1 )
plot(x, y, pch=20)

# basic straight line of fit
fit <- glm(y~x)
co <- coef(fit)
abline(fit, col="blue", lwd=2)

# exponential
f <- function(x,a,b) {a * exp(b * x)}
fit <- nls(y ~ f(x,a,b), start = c(a=1 , b=c(0,1)))
co <- coef(fit)
curve(f(x, a=co[1], b=co[2]), add = TRUE, col="green", lwd=2)


# exponential
f <- function(x,a,b) {a * exp(b * x)}
fit <- nls(y ~ f(x,a,b), start = c(a=1, b=1))
co <- coef(fit)
curve(f(x, a=co[1], b=co[2]), add = TRUE, col="green", lwd=2)
# logarithmic
f <- function(x,a,b) {a * log(x) + b}
fit <- nls(y ~ f(x,a,b), start = c(a=1, b=1))
co <- coef(fit)
curve(f(x, a=co[1], b=co[2]), add = TRUE, col="orange", lwd=2)

# polynomial
f <- function(x,a,b,d) {(a*x^2) + (b*x) + d}
fit <- nls(y ~ f(x,a,b,d), start = c(a=1, b=1, d=1))
co <- coef(fit)
curve(f(x, a=co[1], b=co[2], d=co[3]), add = TRUE, col="pink", lwd=2)

On Tue, Nov 27, 2018 at 12:28 PM Sarah Goslee <sarah.goslee at gmail.com>

wrote:

Hi,

Using rseek.org to search for exponential regression turns up lots of

information, as does using Google.

Which tutorials have you worked thru already, and what else are you

looking for?

Sarah

On Tue, Nov 27, 2018 at 5:44 AM Tolulope Adeagbo <

tolulopeadeagbo at gmail.com> wrote:

Good day,
Please i nee useful materials to understand how to use R for

exponential

regression.
Many thanks.

--
Sarah Goslee (she/her)
http://www.numberwright.com