final Flashcards
-Different participants are observed onetime in each group or at each level of a factor
between-subjects design
Levels of a between-subjectsfactor are manipulated, then different participants are randomlyassigned to each group or to each level of that factor and observedone time
between-subjects experimental design
Type of factor in which different participants areobserved in each group or at each level of the factor
between subjects factor
A statistical procedure used to test hypotheses concerning thedifference between two population means, where the variance in oneor both populations is unknown.
* Making comparisons between two independent groups
two independent sample t test
refers to the selection of participants such that different participants areobserved one time in each sample or group
independent samples
categorical variable (school) with two levels(Towson and JMU)
IV
continuous variable (IQ)
DV
The inferential statistic you use to look at ___between groups is the independentsamples t-test
mean differences
assume data in each population are normally distributed
normality
assume that the data were obtained using a randomsampling procedure
random sampling
each measured outcome is independent; one outcome isnot influenced by any other
independence
assume variance in each population is equal to each other. This is satisfied when larger variance is not greater than two times that of the smaller
equal variances (homogeneity of variances)
how to determine homogeneity v hetero. of variance?
levene’s test
if we reject null, SPSS reports t-test that does not assume…
equal variance
The null states that there is no difference and the alternative states that the difference is different than ___
0
Remember that we will only really report an effect size IF we ___
reject the null
place the difference between two sample means in the numerator and the pooled sample standard deviation in the denominator
estimated cohen’s d
results of t-test
- The value for the test statistic
- Degrees of freedom
- p value
Cohen’s d is most often reported with ___tests
t
participants in each group or sampleare related
related or dependent sample
they are observed in more than one group
repeated measures
They are matched, experimentally or naturally, based on the common characteristics or traits that they share
matched pairs design
repeated measures design
- A research design in which the same participants are observed in each sample.
- This is the most common related samples design
type of repeated measures design in which researchers measure a dependent variable for participants before (pre) and following(post) some treatment
pre-post design
type of repeated measures design where researchersobserve the same participants across many treatments but not necessarilybefore and after a treatment
within-subjects design
Matching through ___ is typical for experiments in which the researcher manipulates the traits or characteristics used to match theparticipants
experimental manipulation
Matching through __ is typical for quasi-experiments in which participants are matched based on their preexisting traits or characteristics
natural occurrence
a statistical procedure used to test hypotheses concerning two related samples selected from populations in which the variance in one or both populations is unknown
* Comparing mean difference between pairs of scores in population to those observed in a sample
related samples t test
score or value obtained by subtracting two scores. In a related samples t test, this is obtained prior to computing the test statistic
difference score
the larger the value, the ___ likely a sample mean difference could occur if the null hypothesis were true
less
The degrees of freedom for the related-samples t test
n-1
we assume thatdifference scores were obtained from different individualswithin each group or treatment
independence w/in groups
An estimate of the proportion of variance in a dependent variablethat can be explained by a treatment
proportion of variance
in hypothesis testing, we are often interested in ___ than two groups
more
is a statistical procedure used to test hypotheses for one or more factors concerning the variance among two or more group means, where the variance in one or more populations is unknown
An Analysis of Variance (ANOVA), also called the F test
one factor tested
one way anova
two factors tested
two way anova
research design in which we select independent samples,meaning that different participants are observed at each level of a factor
between-subjects design
of groups
k
of participants per group
n
of total participants in study
N
any variation that can be measured in a study. In the one-waybetween-subjects ANOVA, there are two sources of variation
source of variation
variance of group means
between groups variation
variation attributed to error
within groups (error) variation
the distribution of possible outcomes for the test statistic is ___ skewed
positively
The distribution, called the F distribution, is derived from a sampling distribution of F ___
ratios
The variances measured in an ANOVA test are computed as ___ squares, or variance
mean
It is computed as mean square (or variance) betweengroups divided by the mean square (or variance) withingroups
F statistic
variance between groups/variance within groups
F obtained
As M1, M2, M3 deviatefrom one another (getfurther apart), their variance will ___
increase
As variances within-conditions ___, discrepancy of the means is less meaningful
increases
As variances within-conditions ___, discrepancy of the means is more meaningful
decrease
statistical procedure computed following a significant ANOVA todetermine which pair or pairs of group means significantly differ
post hoc test
These tests are necessary when k > 2 because multiple comparisons are needed
post hoc
All post hoc tests control for experimentwise ___
alpha
Bonferonni is far too ___
conservative
Tukey’s HSD is most -__
conservative