Margin of Error Calculator

Please input the requested fields

Population Size (N)
Sample Size (n)
Standard Deviation (SD)
Alpha or Confidence Level (α):

Confidence Level is 1-(α). For example, 95% confidence would be .95 or (α)=0.05.



Your Margin of Error (MOE) will appear here when calculated.

































INTERPRETATION:

If the Margin of Error (MOE) is less than or equal to 0.12, then the results are accurate within +/- 3%. This is an optimal level of interpretive validity.

If the MOE is between 0.12 and 0.20, then the results are accurate within +/- 5%.This represents a good level of interpretive validity.

MOE's greater than 0.20 or 5% should be interpretted with caution because this represents low levels of interpretive validity (Royal, 2016).


EXAMPLE:
Class Size (N): 100
Number of Responses (n): 38
Standard Deviation (SD): 0.32
Alpha (α): 0.05 or Confidence Level: 0.95

Margin of Error = 0.0828. The rating is accurate within a range of 3% [0.0803-0.0853].


Citation for Calculator:
Stockdale, M. (2016, August). Calculation for the margin-of-error: An interactive calculation tool for determining the margin of error and interpretive validity of student evaluations of teaching (SET)[Computer software]. Available from http://www.measurementresource.com/MOE.


Relevant Citations:
James, D. E., Schraw, G., Kuch, F. (2015). Using the sampling margin of error to assess the interpretative validity of student evaluations of teaching. Assessment & Evaluation in Higher Education, 40(8), 1123-1141.

Royal, K. D. (2016). A guide for making valid interpretations of student evaluation of teaching (SET) results. Journal of Veterinary Medical Education, (volume, issue and pages are forthcoming). DOI: 10.3138/JVME.1215-201R.










Many thanks to S. Cupidon for his excellent scripting help.