Health Sciences 3801A/B Lecture Notes - Lecture 5: Standard Deviation, Test Statistic, Null Hypothesis
12 Mar 2021
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Document Summary
The t distribution is one of the more important statistical theories that we will discuss this year. It is designed to account for the fact that the sample standard deviation is an imperfect representation of the population standard deviation. It is therefore more appropriate for the identification of statistically significant findings than the z distribution when the population standard deviation is not known. We already learned that the t distribution becomes more similar to the z distribution as the n size increases. We did not, however, explicitly go over what happens as the n size becomes smaller. Given that the t distribution is intended for small sample size inferential statistics, this is potentially interesting in our exploration of the t-test. Note: student"s t distribution always uses a lowercase t. The t distribution becomes increasingly similar to the z distribution as the sample size increases. At 30 degrees of freedom, it is virtually identical to the z distribution df = 30.
