Student’s t test and Nonparametric Statistics OT 667 Hypothesis testing defined A method for deciding if an observed effect or result occurs by chance alone OR if we can argue the results actually happened as a result of an intervention. The Null Hypothesis
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Student’s t test and Nonparametric Statistics
A method for deciding if an observed effect or result occurs by chance alone
if we can argue the results actually happened as a result of an intervention.
In order to decide if the results of an experiment occur by chance or if the effects seen are the result of a treatment, researchers declare a null hypothesis (Ho) and an alternative or research hypothesis (Ha).
To test a hypothesis, researchers talk about “rejecting the null” in order to demonstrate the treatment has an effectOR“accepting the null” if the treatment does not have an effect.
When you reject the null, you say that there IS a significant difference between the groups, indicating the likelihood the treatment was effective.
Interval and ratio
The difference between the group means divided by the difference between the variability within the groups
The variance gives you the degree of variability within each group
Between group differences and within group differences are important factors to remember - they are used to calculate ANOVA as well as t tests.
mean of the difference scores___
standard error of the difference scores
The number that results from a t test is called the “calculated value” of the test. This number is then compared in a table to the “critical value” using the alpha level set for the study.
Independent samples t test
Paired t tests
One way ANOVA
Mann-Whitney U test
Wilcoxon Signed-Ranks Test
Kruskal-Wallis one way analysis of variance by ranks
Friedman Two Way
Remember Venn diagrams and relationships?