comparing means Flashcards
1
Q
what does a t-test do
A
allows us to compare for statistical significance
2
Q
what does a t-test calculate
A
- t-statistic - difference between means in standard errors
- degrees of freedom ( the amount of numbers which we are free to estimate)
- p-value - the probability of finding the t-statistic, if there was no difference in the population
3
Q
what is the paired-samples t-test
A
- a t-test for a within-test design - measure same people at 2 different times
- more powerful than independent sample t-test as more likely to find true effect, less error
4
Q
A
5
Q
what does comparing means allow us to do
A
- to see if a change in an IV leads to a change in a DV
- essential for comparing means
6
Q
what is the p-value
A
- how we tell data from the sample fits the null hypothesis
- significant if p<.05 - less than 5%
7
Q
what is degrees of freedom
A
- the number of parameters which are free to vary
8
Q
what are independent samples t-test
A
- used for between-subjects design
- 2 groups and want to see if they have different means
- each person in one condition
9
Q
how to run an independent t-test on spss
A
- analyse
- compare means
- independent samples t-test
10
Q
where do you find the results for independent samples-test
A
find p value on the grid
11
Q
how do we find if the mean difference is normatively distributed on SPSS
A
- transform
- compute variable
to work out difference - graph
- histogram
12
Q
how to make box plot to compare scores
A
- graphs
- box plots
13
Q
how to calculate related t-test on SPSS
A
- analyse
- compare means
- compare sampled t-test
- two sided p value
14
Q
what is the one-sample t-test
A
- compare mean to test value
- is average different from a given number
15
Q
how to calculate one sampled t-test on SPSS
A
- analyse
- compare means
- one sampled t-test
- decide on variable
- enter test value
