ABSTRACT
The t-test is often used to test the null hypothesis regarding the observed difference between two means. Three interrelated factors are: Sample size. The larger the sample, the less likely that an observed difference is due to sampling errors. Thus, other things being equal, the larger the sample, the lower the value of probability (p). The size of the difference between means: The larger the difference, the less likely that the difference is due to sampling errors. Thus, other things being equal, the larger the difference between the two means, the lower the value of p. The amount of variation in the population. When a population is very homogeneous, there is less potential for sampling error. Thus, other things being equal, the smaller the variability, the lower the value of p. A special type of t-test is also applied to correlation coefficients.
