In response to an unknown trigger, the immune system may begin producing antibodies that instead of fighting infections, attack the body's own tissues. Treatment for autoimmune diseases generally focuses on reducing immune system activity.
What's taught in school. Some of the items in standardized achievement tests measure the knowledge or skills that students learn in school. In certain subject areas, such as mathematics, children learn in school most of what they know about a subject.
The t-test and the one-way analysis of variance (ANOVA) are the two most common tests used for this purpose. The t-test is a statistical hypothesis test where the test statistic follows a Studentâs t distribution if the null hypothesis is supported. This test is applied when the test statistic follows a normal distribution and the value of a scaling term in the test statistic is known.