probability and significance Flashcards
What is a null hypothesis?
States that there will be no difference between the conditions of the IV.
What is the usual significance level in psychology research?
0.05 (5%)
Why is it good to have a 5% significance level in research?
We can never be 100% certain about results. Results could be down to chance.
What is a one-tailed hypothesis?
A directional hypothesis
What is a two-tailed hypothesis?
A non-directional hypothesis
What are the two types of errors?
Type 1 error
Type 2 error
What is a type 1 error?
Claiming that there is an effect when there isn’t
i.e rejecting the null hypothesis and accepting the experimental hypothesis.
What is a type 2 error?
Claiming that there isn’t an effect when there is.
i.e accepting the null hypothesis and rejecting the experimental hypothesis.
At a probability of 0.01 are we more or less likely to make a type 1 error?
Less
At a probability of 0.10 are we more or less likely to make a type 1 error?
More
At a probability of 0.01 are we more or less likely to make a type II error?
More
At a probability of 0.10 are we more or less likely to make a type II error?
Less
How can we avoid a type I error?
Increase stringency of significance level.
E.g move from p=0.05 to p=0.01
How can we avoid a type II error?
Decrease stringency of significance level.
E.g move from p=0.01 to p=0.05
What are the consequences of a type I error?
-The researcher publishes false data and other researchers waste precious time and resources trying to replicate the study.
-Scientific journals waste resources in publishing replicating research.
