Problem-Solving Resource Center

Tests of Significance

What It Is Used For

  • To statistically determine if a sample represents a population or if two or more samples are from the same population.

When to Use It

  • To confirm that an improvement is truly an improvement and not just common cause variation in the process.

Important Notes

  • t-tests use sample means to look at the location of the process output relative to a known population or to another population (represented by another sample mean).
  • F-tests are used to compare the variances of two samples to determine if the variation between the two populations they represent are likely to be equal.

Example of a test of significance