Stat Calculator – Margin of Error

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Statistical Tool for Calculating the Margin of Error in Survey Data Analysis

The term “margin of error” can be used to mean
sampling error in general. In media reports of poll results, the term usually refers to the maximum margin of errorfor any percentage reported from that poll. The margin of error is a statistic expressing the amount of random sampling error in a survey’s results. The smaller the margin of error, the more trust you can place that the survey’s reported results are “true” (that is, representative of the larger population).

Basic Statistical Testing for Margin of Error
Between Two Proportions/Percentages

Step 1:
Desired confidence level: 99% 95% 90%

Step 2:
Proportion: %

Step 3:
Sample size:

Step 4:
Population size: infinite actual/estimated
  • use ‘infinite’ when the group is larger than 1, or you don’t know
    the actual size of the overall population


Margin of error:? %

see formula

Basic Statistical Testing for Margin of Error
Between Two Means

Step 1:
Desired confidence level: 99% 95% 90%

Step 2:
Standard deviation:

Step 3:
Sample size:

Step 4:
Population size: infinite actual/estimated:
  • use ‘infinite’ when the group is larger than 1, or you don’t
    know the actual size of the overall population


Margin of error:
±

see formula