Inferential statistics Flashcards
Why are IS used?
When collecting data as part of research, a psy will always find a diff or relationship between measures. IS are used by researchers to establish if the diffs/ relationships are sig (large) enough to support their research hypotheses or whether they could have juts happened by chance - thus you can state that any diff/ relationship is due to chance in ur null hypothesis.
probability level definition?
a numerical measure of the likelihood that somehing could happen. e.g. P<0.05
Significance level definiton?
This is a level of probability that a diff/ relationship between sets of data occurred by chance. the sig level determines when a researcher will accept their research hypothesis, which is generally accepted as 0.05. However, some researchers will want to have a more strict level of sig such as 0.005
what is a level of significance represented by?
P and then ,= ect
If the results of a study are equal to ot less than the sig level, then?
the researcher can be confident they did not occur by chance and accept their research hypothesis.
if the results are higher than the significance level, then?
chance may ahve played a part and they accept their null hypothesis
Observed value is?
the number calculated using the ST and is compared to the CV to establish if there is a sig diff or correlation between the 2 or more sets of data.
When will the OV also be the correlation coefficient?
- when establishing sif using A Spearman Rank Order Correlation Coefficient Test or Chi squared test
What is the letter symbolising the OV for Chi Squared test?
X(^2)
What is the letter symbolising the OV for Mann Whitney U test?
U
What is the letter symbolising the OV for Sign test?
S
What is the letter symbolising the OV for Spearman Rank order Correlation coefficient?
R
What is the letter symbolising the OV for Wilcoxon Signed Matched Pairs ?
T
Critical value: -
The value to which the observed value is compared to establish if it is significant. Critical values are located on a critical value table
To identify a critical value for all tests except the Mann
Whitney U test, use the following steps:
- Establish if you are carrying out a one-tailed or two-tailed test. A one-tailed test supports a directional hypothesis and two-tailed test
supports a non-directional hypothesis. - Find the appropriate significance level using the one-tailed or two-tailed test level of significance row.
- Identify your N value (df value if you are using a Chi Squared test) which is the number of sets of data and generally the number of participants in the left hand column.
- Your critical value can be found using the significance level column and the N value row.