# Math Insight

### Applet: Fitting a linear model to population change as a function of population size

In the table of the right panel, enter up to six values for the population size $P_t$ at time $t$. (In the right panel, $P_t$ is displayed as P_t.) The applet will automatically calculate the changes $P_{t+1}-P_t$ and plot the points $(P_t,P_{t+1}-P_t)$, which show the population change versus the population size at the beginning of the interval. By moving the points $A$ and $B$ (represented by the red diamonds) with the mouse, you can try to fit a line through the points and read off its slope. You can zoom in and out with the buttons label by + and -. The arrows allow you finer control over the zoom in each direction.

Applet file: population_change_versus_population_line.ggb

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#### General information about Geogebra Web applets

This applet was created using Geogebra. In most Geogebra applets, you can move objects by dragging them with the mouse. In some, you can enter values with the keyboard. To reset the applet to its original view, click the icon in the upper right hand corner.

You can download the applet onto your own computer so you can use it outside this web page or even modify it to improve it. You simply need to download the above applet file and download the Geogebra program onto your own computer.