T-test (paired and unpaired)
- unpaired t-test (also known as the student's t-test) and the paired t-test both assume that analysed data is from a normal distribution
- unpaired t-test
- applied to two independent groups e.g. diabetic patients versus non-diabetics
- sample size from the two groups may or may not be equal
- in addition to the assumption that the data is from a normal distribution, there is also the assumption that the standard deviation (SD)s is approximately the same in both groups
variable | diabetes Mean (SD) | No diabetes Mean (SD) | Mean difference 95% CI | p-value |
Age (years) | 68.8 (8.7) | 73.3 (9.0) | 4.2 (3.1, 5.3) | p <0.0001 |
Heart rate (bpm) | 75 (15.0) | 76.1 (14.9) | 1.1 (-0.9, 3.1) | p 0.85 |
- paired t-test
- data is derived from study subjects who have been measured at two time points (so each individual has two measurements). The two measurements generally are before and after a treatment intervention
- 95% confidence interval is derived from the difference between the two sets of paired observations
Reference:
- Doctor (March 22nd 2005):33-35.
Related pages
Create an account to add page annotations
Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.