This session is concerned with summary statistics for interpoint correlation (i.e. dependence between points) and simulation envelopes.
The lecturer’s R script is available here (right click and save).

### Exercise 1

The swedishpines dataset was recorded in a study plot in a large forest. We shall assume the pattern is stationary.

1. Calculate the estimate of the $$K$$-function using Kest.

2. Plot $$\widehat K(r)$$ against $$r$$

3. Plot $$\widehat K(r) - \pi r^2$$ against $$r$$.

4. Calculate the estimate of the $$L$$-function and plot it against $$r$$.

5. Plot $$\widehat L(r) - r$$ against $$r$$.

6. Calculate and plot an estimate of the pair correlation function using pcf.

7. Draw tentative conclusions from these plots about interpoint interaction in the data.

### Exercise 2

For the swedishpines data:

1. Plot the $$K$$ function along with pointwise envelopes from 39 simulations of CSR:

plot(envelope(swedishpines, Kest, nsim=39))
2. Plot the $$L$$ function along with pointwise envelopes from 39 simulations of CSR.

3. Plot the $$L$$ function along with simultaneous envelopes from 19 simulations of CSR, using ginterval=c(0,0.5).

4. Plot the $$L$$ function for along with simultaneous envelopes from 99 simulations of CSR using ginterval=c(0,0.5). What is the significance level of the associated test?