Research Methods - Statistical Testing Flashcards
What is the null hypothesis
The hypothesis that says there will be no difference or relationship between two things.
What is the experimental hypothesis
The hypothesis that says there is a difference or relationship between two things.
What are the difference between directional hypothesis and non directional hypothesis
Directional - states the direction of the difference
Previous research involved
Non directional - not stating the direction of the difference
No previous research
What is aim of statistical tests
allow us to decide which hypothesis we are accepting and which we are rejecting.
can assess the probability (likelihood) of results occurring due to chance
What is the accepted level of probability in psychology
0.05 (5%)
P= <0.05
What are psychologists happy to accept
there is a 5% (or less) chance that there is not a difference/relationship between two things because not all members of the population can be tested in all possible circumstances
When do we accept the experimental hypothesis
There is a 5% (or less) probability that the results occurred by chance
Null hypothesis rejected
When do we accept null hypothesis
There is more than a 5% probability that the results occurred by chance
Difference not due to manipulation of IV
The experimental/alternative hypothesis is rejected
What are the two types of error
Type one error
Type two error
In type 1 error which hypothesis is incorrectly accepted and rejected
Accepted incorrectly - the experimental hypothesis
Rejected incorrectly - null hypothesis
Correct - null
What does type 1 error mean
Results actually due to chance so null hypothesis should be accepted but researcher concluded there is a significant difference/ relationship when there’s isn’t one
Experimental hypothesis wrongly accepted
Why do type 1 errors happen
The significance level is too lenient
Eg 10%
10% is quite large believe they have found an effect that doesn’t actually exists
How to prevent type 1 errors
Significance level should be made stricter
More risk to type 2 errors though
Which incorrect hypothesis accepted and and which correct one rejected in type 2 errors
When null hypothesis is wrongly accepted when should be rejected and experimental hypothesis wrongly rejected
what does type 2 errors mean
Null accepted and experimental wrongly rejected Researcher concluded that there is no effect and no real difference/ relationship when there is
Results not due to chance Even if said by researcher they are
