A human factors psychologist wants to know if a new computer-generated voice is either easier or harder to comprehend than human
speech. To test this, he gathers 30 volunteers and assigns each to one of two groups. Both groups hear a selection being read. One group's selection is read in the computer-generated voice, the other is read by a human. The results of the experiment, the number of words from the selection that were transcribed correctly, are presented below. Is there a difference in comprehensibility
Independent test using the t-test. The independent t-test compares the mean of two different groups. It determines whether there is any statistical evidence that is associated with the population means that is different. The independent t-test is a parametric test.