Living Graph: Explore Dispersion Analysis
This exercise allows you to manipulate the grid size used in the Poisson analysis. For each grid size you choose, the program calculates the Poisson distribution and the mean/variance ratio.
- Record the grid size, mean number of individuals, the variance and the mean/variance ratio for the initial graph.
- Change the grid size to several larger and smaller grid sizes. Record the mean, variance and mean/variance ratio for each.
- On a piece of graph paper, label the x-axis Number of Grid Squares and the y-axis mean/variance ratio. Plot the mean/variance ratio as a function of grid size. Describe how the mean/variance ratio changes as the grid size changes.
For the current grid size the mean number of individuals in each grid square is: [calculating...].
The variance in the number per square is [calculating...].
The mean/variance ratio is [calculating...].
Enter a value in the grid size field and click 'Update Graph' to refresh the random distribution of individuals on the graph.
The grid-like graph plots 0 to 10, versus 0 to 10. Dots are distributed all across the grid.