2013, Number 3
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Rev Med Inst Mex Seguro Soc 2013; 51 (3)
Clinical research XV. From the clinical judgment to the statistical model. Difference between means. Student’s t test
Rivas-Ruiz R, Pérez-Rodríguez M, Talavera JO
Language: Spanish
References: 13
Page: 300-303
PDF size: 243.88 Kb.
ABSTRACT
Among the test to show differences between means, the Student t test
is the most characteristic. Its basic algebraic structure shows the difference
between two means weighted by their dispersion. In this way, you
can estimate the p value and the 95 % confi dence interval of the mean
difference. An essential feature is that the variable from which the mean
is going to be calculated must have a normal distribution. The Student
t test is used to compare two unrelated means (compared between two
maneuvers), this is known as t test for independent samples. It is also
used to compare two related means (a comparison before and after
a maneuver in just one group), what is called paired t test. When the
comparison is between more than two means (three or more dependent
means, or three or more independent means) an ANOVA test (or an
analysis of variance) it is used to perform the analysis
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