Research Methods Y1 - Statistical Testing Flashcards
What is the definition of “Statistical testing”?
Provides a way of determining whether hypotheses should be accepted or rejected. In psychology, they tell us whether differences or relationships between variables are statistically significant or have occurred by chance.
What is the “Sign test”?
A statistical test used to analyze the difference in scores between related items (e.g., the same participant tested twice). Data should be nominal or better.
What is the generally accepted level of probability in psychological research?
The level of probability in psychology is 0.05 (or 5% when written as a percentage). This is the level at which the researcher decides to accept the hypothesis.
What does it mean if a result is accepted at the 0.05 level of probability?
This means there is less than 5% probability that the results occurred by chance. In simple terms, this means researchers can be pretty confident that the difference found was because of the manipulation of the independent variable (though there will always be 5% doubt even if significance is found).
Under what circumstances might stricter significance levels, such as 0.01 (the 1% level), be used?
This is used in cases where research may involve human cost, such as when new drugs are being trialed, or when a particular investigation is a one-off, and there is no opportunity that it can be repeated in future.
What are the steps involved in using the sign test to determine if a difference is significant?
We need to be looking for a difference rather than an association.
We need to have used a repeated measures design.
We need data that is organized into categories, known as nominal data.
What are the three pieces of information required to locate the critical value for a sign test?
The significance level desired (always 0.05 or 5% except in the cases described above).
The number of participants in the investigation (the N value).
Whether the hypothesis is directional (one-tailed) or non-directional (two-tailed).
How is the calculated value of the sign test compared with the critical value?
When the calculated value of the sign test (referred to as S) is equal to or less than the critical value for the chosen level of significance, the result is regarded as significant.
What happens if a participant has the same score under both conditions of the sign test?
This data would be ignored and the total N number would be adjusted.
What does it mean if the difference found is statistically significant?
This means the difference found is unlikely to have occurred by chance. If it was significant at the 0.05 level, there is less than a 5% probability the result happened by chance.
