Calculators

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There are hundreds on interactive statistics calculators online. Chances are, if you’re looking for one, it’s because you don’t have SPSS, SAS, or Systat and you need a quick and simple solution. Here are a few easy calculators that will meet most of the basic needs a market researcher may have.

If you’re already fairly familiar with how statistics work, try this site from Evan Miller or this site from Social Science Statistics.  If you need something a little more straightforward, the following sites will suit your needs.

Chi-Square

To determine if the percentage for one group of people is significantly different from the percentage for another group of people.
Example: If 38% of men like nanaimo bars and 43% of women like nanaimo bars, is that difference statistically significant?
Do one here: GraphPad QuickCalcs

T-Test

To determine if the average value for one group of people is significantly different from the average value for another group of people.
Example: If squirrels eat an average of 12.4 peanuts per day and bluejays eat an average of 7.8 peanuts per day, is that difference statistically significant?
Do one here: GraphPad QuickCalcs

Sample size

Statistics are highly dependent on sample sizes. You could find a very large difference between groups that isn’t statistically significant just because the sample size isn’t large enough. But, don’t think that just because a tiny difference is  significant with a sample size of a million doesn’t mean that it’s a meaningful difference.
Example: If 30% of researchers like buttertarts and 38% of marketers like buttertarts, what sample size will I need to confirm this is a statistically significant difference?
Do one here: DSS Research Calculator

Effect Size

Is the difference between two average numbers meaningful? Being statistically significant is insufficient to say if the difference is important.
Example:  Let’s assume children can eat an average of 17.4 macaroons and adults can eat an average of 17.6 macaroons, and that difference is statistically significant. Is the difference of 0.2 macaroons a meaningful difference? (And I hope you don’t need a calculator to conclude for yourself that this is NOT an important difference.)
Do one here: Daniel Soper

Random Number generator

Exhaustive lists for the statistically insane:

StatPages
Daniel Soper collection
GraphPad Software
easy calculation
Educypedia