This is a simulation of finding a confidence interval for a proportion where the user can select the population proportion, the confidence level, sample size, and whether to simulate one or 25 confidence intervals.
It simulates the process of taking an election poll involving two candidates. Some proportion p of the population plans to vote for candidate A. If we sample n people from the population, the proportion of people in the sample who say they plan to vote for candidate A is our best estimate of the population proportion. We can then construct a level C confidence interval, where C is the probability that the interval actually includes the true value of p. More specifically, the confidence interval is calculated as the sample proportion ± z* times the standard deviation of the sample proportion, where z* is the critical value of z that has (1-C)/2 of the normal distribution to the right of the value, and the standard deviation is.
Type of Material:
Simulation
Recommended Uses:
In class, homework, individual, team.
Technical Requirements:
Javascript enabled browser
Identify Major Learning Goals:
To gain an understanding of a confidence interval for a proportion, that is, the best estimate of the population proportion.
Target Student Population:
Students in an Elementary Statistics class
Prerequisite Knowledge or Skills:
The basic idea of a confidence interval
Content Quality
Rating:
Strengths:
This site allows the student to choose the population proportion, the confidence level, and the sample size. It then clearly displays the randomly generated confidence intervals color coded to show whether or not the interval contains the population proportion and the percent of the confidence intervals that do contain the population proportion.
The applet provides a complete demonstration of the conncept
Concerns:
It would be helpful to provide a link to a page that provides information about confidence intervals for a population proportion. Also, the instructions state that this is about an election poll, but the activity is about confidence intervals for a proportion in general rather than an election poll specifically.
The applet does not integrate well the concept because statistics is not only calculus, it has to provide a background or context that helps understand the use of statistics and to develop the right attitude for use it.
Potential Effectiveness as a Teaching Tool
Rating:
Strengths:
This simulation will clearly demonstrate to the student what a confidence interval for a proportion is all about and what the confidence level represents. It can be used in part of the lecture on confidence intervals and for student exploration.
It helps to build on prior concepts and also demonstrates relationships between concepts
Concerns:
It would be helpful to provide the student learning outcomes such as to see the CI as a tool making decision and some questions that will help students focus on the concepts that the simulation is designed to strengthen, such as the fact that if many confidence intervals are constructed, then the confidence level is approximately the proportion of the confidence intervals that will contain the population proportion.
Ease of Use for Both Students and Faculty
Rating:
Strengths:
This site is easy to use with very clear instructions. It is visually appealing. This simulation includes sliders for each of the parameters.
Concerns:
Customize for a particular purpose, statistics is more than a poll! The applet demonstrate how to use the CI but not when to use it, for this is very important to provide the student learning outcomes.
Creative Commons:
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