RESEARCH METHODS: The Sign Test Flashcards
What is statistical testing?
Provides a way to determine whether hypothesis should be accepted or rejected. By using statistical tests we can find out whether differences or relationships are significant or if they are likely to have occurred by chance.
What is the sign test?
Statistical test used to analyse the difference in scores between related items. It is used to determine whether a difference is statistically significant.
What is required to use the sign test?
- Looking for a difference rather than an association
- Experiment need to have used repeated measures design ( same group and different conditions )
- Data must be nominal - organised in categories
What is the definition of probability ?
Probability (p) refers to the likelihood that certain events would occur
What is the accepted level of significance in psychology ?
0.05 = 5%
What is the probability if the hypothesis is ACCEPTED?
there is less than 5% probability that the results occurred by chance. This means the researcher is very sure that their results were due to the manipulation of the IV.
What is the probability if the hypothesis is rejected?
There is more than 5% probability that the results occurred by chance. This means that the researcher is very sure that the results happened by chance and NOT due to the manipulation of the IV.
Why is 0.01 probability used by researchers?
It is used when the researcher needs to be more confident and eliminate as much as possible
What can 0.01 probability be used in?
In studies which may affect human lives. Eg a new drug being trialled
Eg if that study is a one-off and won’t ever be repeated again
How do you complete the sign test?
STEP 1 -
-if any participants recalled the same amount in both conditions, their data must be removed + number of participants must be reduced.
- convert the data into nominal data.
STEP 2-
-add the pluses and minuses and find the less frequent sign (s). This is the calculated value.
STEP 3-
compare your calculated value with the critical value
How can the critical value be found?
- critical values table ( which will be given)
You need to consider whether your experiment is. - one-tailed or two-tailed
- what is the significance level being used? p=0.05
- how many participants
What does it mean when the results are significant?
The calculated value must be less than the critical value at 0.05 significance.
(S) calculated value < critical value
state if the hypothesis is a one tailed or two tailed test?
one-tailed - directional hypothesis
two tailed- non-directional hypothesis
