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Peer Review

Confidence Interval for a Mean

by Larry Green


Overall Numeric Rating:

4.33 stars
Content Quality: 4 stars
Effectiveness: 4 stars
Ease of Use: 5 stars
Reviewed: Nov 27, 2004 by Statistics Editorial Board
Overview: This Java based applet gives students an opportunity to work through confidence
interval problems for the mean. The material provides written word problems in
which an individual must be able to correctly identify the given parts for a
confidence interval calculation, and then be able to use this information to
find the confidence interval. It gives step by step prompts to encourage
students to choose the correct numbers and "cast of characters".
Type of Material: Java Applet
Recommended Uses: This site can be used as an out of class assignment for students who want to
practice additional problems. It is excellent for basic remedial activity. The
lack of a "scoring method" makes it unsuitable for a graded homework assignment.
Technical Requirements: Java capable web browser. A student will also need a calculator to do
calculations required.
Identify Major Learning Goals: 1. Correctly identify the essential parts for a confidence interval calculation
in a word problem.
2. Use the information obtained from that word problem to calculate the
confidence interval.
3. Become familiar with the terminology associated with calculating confidence
intervals (i.e. margin of error,x-bar,zc,..).

Target Student Population: Students in introductory statistics including students enrolled in high school
AP courses.
Prerequisite Knowledge or Skills: Students shold have knowlege of statistical notation, have learned the structure
of a confidence interval, and understand terminology such as x-bar, standard
deviation, and margin of error.

Evaluation and Observation

Content Quality

Rating: 4 stars
Strengths: The applet is very simply organized and helps students to develop step by step
processes for solving confidence interval problems. This applet requires
students to identify component parts of the confidence intervals. The structure
of the applet forces students to identify constituent parts of the problem that
will be used in the calculation of the confidence interval. The material has a
nice display with easy to understand directions and an interface with
encouraging and helpful help windows that pop-up when an incorrect answer is
Concerns: Most of the applet is a "plug and chug", which is good for students having
difficulty identifying the essential parts of a confidence interval calculation
from word problems, but does not encourage conceptual thinking about confidence
intervals. The student is not asked to identify the population of interest or
the parameter that the confidence interval is expected to contain nor does the
applet provide a graphical illustration of the confidence interval.

Potential Effectiveness as a Teaching Tool

Rating: 4 stars
Strengths: The teaching-learning goals of the material are easy to identify. The material
is relevant to most introductory statistics textbooks, and it is easily
accessible. The material is well organized and presented. The help windows are
well designed to aid students through the process.
Concerns: It does not give students any encouragement to think about the assumptions
made in constructing the interval and thus does not encourage critical thinking
about confidence intervals. There are also minor grammatical errors and some
issues with the display of digits that might cause some problems.

Ease of Use for Both Students and Faculty

Rating: 5 stars
Strengths: The material has a very nice display that is easy to use and follow. The
directions are clear and the help boxes are helpful with the right amount of
information. The material can be used with a variety of different backgrounds
and/or technical skills.


Other Issues and Comments: <