L24 - Probability and Significance Levels Flashcards
what is the LEVEL OF STATISTICAL SIGNIFICANCE?
The LEVEL at which the decision is made to REJECT THE NULL HYPOTHESIS IN FAVOUR OF THE EXPERIMENTAL HYPOTHESIS
It states HOW SURE WE CAN BE that the IV IS HAVING AN EFFECT ON THE DV and this is NOT DUE TO CHANCE
what is CHANCE in relation to SIGNIFICANCE?
Something has NO REAL CAUSE, it JUST HAPPENS, the even is NOT HAPPENING DUE TO MANIPULATION OF THE IV, its JUST HAPPENING
what are SIGNIFICANCE LEVELS?
Using STATISTICAL TESTS we can determine whether or not RESULTS OF AN EXPERIMENT represent SIGNIFICANT DIFFERENCES or NOT
When we are doing this we have to APPLY AN APPROPRIATE SIGNIFICANCE LEVEL which will determine the LEVEL at which the RESULTS ARE DEEMED SIGNIFICANT (NOT DOWN TO CHANCE)
what is PROBABILITY?
PROBABILITY is a NUMERICAL MEASURE that determines whether our RESULTS ARE DUE TO CHANCE or whether there is a REAL DIFFERENCE that exists BETWEEN THE EXPERIMENTAL and CONTROL CONDITIONS
If a REAL DIFFERENCE exists we can say that the RESULTS ARE SIGNIFICANT, and the NULL HYPOTHESIS CAN BE REJECTED
which SIGNIFICANCE LEVELS should we use in PSYCHOLOGY?
The CONVENTIONAL and STANDARD LEVEL OF SIGNIFICANCE in psychology is expressed as p<0.05 (5% LEVEL)
This is a good significance level because it is NOT TOO STRICT and NOT TOO LENIENT but a MIDDLE, FAR VALUE OF SIGNIFICANCE
This significance level means that there is only a 5% PROBABILITY that the results are DUE TO CHANCE and a 95% chance that the results are representing REAL DIFFERENCE
what is a TYPE 1 ERROR?
When we REJECT THE NULL HYPOTHESIS and ACCEPT THE EXPERIMENTAL HYPOTHESIS even though the RESULTS OF THE STUDY ARE ACTUALLY DUE TO CHANCE and are NOT STATISTICALLY SIGNIFICANT
A TYPE 1 ERROR is called a FALSE POSITIVE
This error occurs when the LEVEL OF SIGNIFICANCE is TOO LENIENT
what is a TYPE 2 ERROR?
When we FAIL TO REJECT THE NULL HYPOTHESIS even though we SHOULD HAVE REJECTED IT BECAUSE THE RESULTS WERE ACTUALLY SIGNIFICANT
A TYPE 2 ERROR is called a FALSE NEGATIVE
This error occurs when the LEVEL OF SIGNIFICANCE is TOO STRICT
