š§® ā¢ Statistics: Wilcoxon [āļø] Flashcards
List all the steps for working out Wilcoxonās Statistical Test of Significance
- Calculate the difference between two scores by taking one away from the other (A-B)
-
Rank the differences giving the smallest value (difference) a Rank of 1
* If a difference results in 0 you no longer use this in the calculation e.g. when calculating N or adding up scores - Add up the ranks for all positive differences
- Add up the ranks for all negative differences
- T (the symbol given to the outcome of this test) is the figure that is the smallest when the positive & negative ranks are totalled
- N = the number of scores, ignoring those with a difference of 0
What do you do after you have calculated the T value?
You take your calculated value of T and apply it to the critical value table to check for a statistical significance
What do you then have to look for and use to compare the newfound critical value and your calculated (T) value in order to determine if the results for the experiment were signifiant or not?
The rule at the bottom of the critical value table that indicates the threshold for significance e.g:
The calculated value must be equal to or less than the critical value in this table for a significance to be shown
By comparing, you will then be able to see if the resuls of the experiment were significant or not
Why do you always have to make sure to properly read the rule of significance at the bottom of the critical values table?
Because it may be different for each critical values table you come across/ each exam you go into
What might you then have to do after using the critical values table and your calculated value to determine significance?
Write a statistical statement
What 8 things must you include in a statistical statement?
- Your Calculated Value (T)
- Your Critical Value
- If it is Greater or Less than the Critical Value (š¢)
- What direction (one/two-tailed) the level of significance you used was
- What the level of significance you used was (0.05)
- If it was/ wasnāt statistically significant (š¢determined by)
- Which hypothesis it supports
- The hypothesis it supports (Write entire hypothesis
Complete the question on ranking scores
What ātypeā of value do you obtain after completing the Wilcoxon calculation?
The Calculated Value
What ātypeā of value do you obtain after using the critical values table?
The Critical Value
What do you always have to make sure you first, choose on a critical values table?
The correct level of significance for the type of test you need.
* Dependent on our HYPOTHESIS, we either choose:
* the level of significance for a one-tailed test
* the level of significance for a two-tailed test
e.g. if hypothesis was two-tailed you would use level of significance for two-tailed test
What level of significance do you ALWAYS choose in a critical values table?
0.05
