Independent Tests Flashcards
what are independent t-tests?
compares the means of two independent groups
what do independent t-tests require?
parametric assumptions must be met
assuming the null hypothesis is true means that…
any difference is result of sampling variability and the two sets of scores come from the same population distribution
however, it may be…
that our difference reflects a real difference between the populations
what does SPSS output provide for a descriptive statistics of a t-test?
the mean and SD
what does SPSS output provide for inferential statistics of a t-test?
t-statistics, degrees of freedom, and p-value
t-value
this is important regardless of being positive or negative
when should the row of equal variances not assumed be met?
or using an equivalent non-parametric test
when there is a significant difference between group variances
write up of an independent t-test
an unrelated t-test found that the female group scored significantly higher than the male group t(14) = 2.409, p=0.03
mann-whitney u test
- all observations from both groups are independent
- responses are at least ordinal level
- parametric assumptions do not need to be met
mann-whitney u null hypothesis
assumes the distribution of both groups is equal
what must be assumed when using a mann-whitney u test?
the probability of an observation from one population (X) exceeding an observation from the second population (Y) is more than 0.05
MW: what does SPSS output provide?
N and a mean rank
along with U-value, z-score, and p-value
what does MW write up require?
u-value, z-value, p-value
how are descriptive statistics reported for MW?
through the medians
