Sample from a population

The applet below allows for the visualization of taking a sample from a population. The top plot displays the distribution of a population. Several options are available for the population distribution (Uniform, Bell shaped, Skewed, Binary and Custom). Each distribution can be changed interactively by clicking and dragging the mouse along the plot tracing out the shape of the desired distribution. The Custom option provides a blank plot on which a distribution can be constructed. When the Sample button is clicked, a random sample of size n will be selected from the population and displayed in the bottom plot. If the Animate option is checked, the display will show the points selected from the population dropping into the bottom plot. To stop an animation uncheck the Animate option. Summary statistics for the population and the sample are shown in the panel to the left of each plot. Things to try with the applet:

  • For each population distribution, experiment with generating samples of different sizes. How large does the sample size need to be before the sample begins to look like the population?
  • For each population distribution, experiment with generating samples of different sizes. How large does the sample size need to be before the summary statistics for the sample are close to the summary statistics for the population?