Estimate the proportion of orange balls in the large jar.
Choose samples and create confidence intervals to estimate the proportion of orange balls in the large jar.
- Use the '1 CI' button to generate and plot a single confidence interval.
- Each time the button is pressed, a new sample from the 'population' jar is chosen and placed into the 'sample' jar.
- The sample number and the number of orange balls in the sample are displayed.
- When the '100 CI' button is pressed, the applet will choose 100 random samples and compute a confidence interval for each.
- Use the radio buttons below the plot to change the confidence level.
- Use the spinner to change the sample size (this will clear the plot but will not affect the population).
- When the 'show parameter value' checkbox is selected,
- a line marking the percentage of orange balls in the population jar is displayed on the plot.
- confidence intervals that do not cover the true percentage are displayed in green.
- Press 'Reset' to clear the plot and obtain a new population of balls.
- Press 'Clear' to clear the plot without obtaining a new population of balls.
Options Menu :
Use the 'Options' menu to change the animation speed or confidence bar thickness. This menu can also be used to choose to estimate the
percentage of orange balls in the population rather than the proportion.
Questions to Consider:
- As the confidence level increases, do the intervals generally get wider or more narrow? Explain.
- As the sample size increases, do the intervals generally get wider or more narrow? Explain.
- When 100 confidence intervals are generated, why are they all different?
- If the confidence level selected is 90%, about how many of 100 intervals will cover the true percentage of orange balls? Will exactly
this number of intervals cover the true percentage each time 100 intervals are created? Explain.