Peer Review

Calculating the Required Sample-Size

Material Detail page

Reviewed:: Jun 24, 2005 by Business

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Ratings

Overall Rating:

Content Quality:

Effectiveness:

Ease of Use:

Overview:: The module provides a short simulation to calculate the required sample size.
Students input the percentage error, response rate, confidence range, and the
confidence level to receive the sample size needed. In addition, the website
helps researchers calculate the required sample size for a market research
study.
Type of Material:: The material is an online calculator to compute required sample size. It is
one tool contained within a broader website on database marketing.
Recommended Uses:: This would be appropriate to use when discussing how to determine sample size in
a graduate or undergraduate marketing research class, or in any research
focused course.
Technical Requirements:: Access to the Internet is required in order to use this material.
Identify Major Learning Goals:: The major learning goal is to illustrate what drives sample size in a market
research study. Secondary learning goals include: 1) illustrating how to
quickly calculate the required sample size (although the specific formula to
calculate is not offered), and 2) providing a brief introduction to database
marketing.
Target Student Population:: The target population includes students enrolled in a marketing research class,
a general business statistics course, or a class involving database marketing as
part of their curriculum. This module would be appropriate for undergraduate
or graduate students.
Prerequisite Knowledge or Skills:: Students would need to be familiar with the statistical terminology found on the
website. For instance, they would need to know what is meant by response rate,
allowed percentage error, z-scores, standard deviation, and confidence level.

Content Quality

Rating:
Strengths:: The strength lies in its ability to quickly compute the required sample
size. The material is very straightforward and very easy to use. The
calculator uses the basic formula for sample size and once the appropriate
information is entered in the website, the sample size is calculated.
Concerns:: If the user does not understand the terminology, this tool is useless to the
student. For instance, if the user does not know what is meant by confidence
level, this tool does not provide any clarification. Also, no additional
information or explanation as to what drives sample size (i.e., the underlying
formula) is presented. Furthermore, it would have been good if the website
offered explantions for confidence range, level, etc.

It may be easier for students if the calculator simply asked them to enter the
margin of error, confidence level and population size (if known). The
calculations from this calculator seem extremely high and the validity of
results can be questioned.

Potential Effectiveness as a Teaching Tool

Rating:
Strengths:: An instructor could use this website when discussing the calculation of sample
size. By manipulating the variables that determine sample size, students could
quickly see how sample size fluctuates.
Concerns:: The formula for calculating sample size is not that complicated. Showing the
students the formula, explaining the various components, and allowing them to
calculate sample size on their own, seems like a more valuable learning
experience than simply plugging numbers into a website. Students probably
should not use this calculator without proper instruction beforehand. An
alternative application, would be one that simply asks for margin of
error, confidence level and population size.

Ease of Use for Both Students and Faculty

Rating:
Strengths:: If students understand the terminology on the website, this is a very easy tool
to use.
Concerns:: If students do not understand the terminology on the website, this tool becomes
incredibly confusing and difficult to use.

Other Issues and Comments:: While this could be used as a teaching tool, it seems more appropriate for use
as a resource for marketing researchers. For instance, if someone was designing
a study and quickly needed to calculate sample size, this would be a great
website to go to, quickly plug in the appropriate information, and the
required sample size would be calculated.
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