Uploaded May 2012 | Updated September 2026, 1 hour ago
I discuss an example of the paired-difference t procedure, working through a confidence interval and hypothesis test and interpreting the results. (Paired-difference procedures are sometimes referred to as matched-pairs procedures, depending on the setting.)
The identical twin-schizophrenia data in this video is from:
Suddath, R., Christison, G., Torrey, E., Casanova, M., and Weinberger, D. (1990). Anatomical abnormalities in the brains of monozygotic twins discordant for schizophrenia. New England Journal of Medicine, 322:789--794. Values used in this video are simulated values based on the summary statistics found in the paper.
I discuss an example of the paired-difference t procedure, working through a confidence interval and hypothesis test and interpreting the results. (Paired-difference procedures are sometimes referred to as matched-pairs procedures, depending on the setting.)
The identical twin-schizophrenia data in this video is from:
Suddath, R., Christison, G., Torrey, E., Casanova, M., and Weinberger, D. (1990). Anatomical abnormalities in the brains of monozygotic twins discordant for schizophrenia. New England Journal of Medicine, 322:789--794. Values used in this video are simulated values based on the summary statistics found in the paper.





![Introduction to the t Distribution (non-technical)
A brief non-technical introduction to the t distribution, how it relates to the standard normal distribution, and how it is used in inference for the mean.
For those that use R, below are the R codes to find the values found in the video.
z value for a 95% interval:
qnorm(.975)
[1] 1.959964
t value for a 95% interval (5 DF)
qt(.975,5)
[1] 2.570582
t value for a 95% interval (10 DF)
qt(.975,10)
[1] 2.228139 Introduction to the t Distribution (non-technical)](https://i.ytimg.com/vi/Uv6nGIgZMVw/mqdefault.jpg)




