The symptoms of a sty are. foreign body sensation in the eye (particularly with blinking), eye pressure, and; pain in the area of the bump, though often they are painless. There may also be blurred vision if thick sebum or pus from within the sty spreads over the eye's surface. If chronic meibomian gland dysfunction is present, dry eye symptoms are common.
Paired t-test. This tutorial will walk you through the use of the paired t-test. The paired t-test should be used when the data are in pairs. One of the most common uses of this test is a before- and after- (pre and post) analysis. For example, we might be interested in how much a certain group grows after fertilizer is added to randomly selected plots.
The t test is a two-tailed test because the tail of the distribution on each side of the mean is analyzed. For many laboratory measurements or clinical trials, one would want a two tailed test because the value or the outcome could be either above or below the mean.