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Flashcards in Statistics Deck (31):
1

Mann-Whitney U Test

one independent variable - two independent groups
one dependent variable - rank-ordered data

2

Wilcoxon Matched-Pairs Signed-Ranks Test

one independent variable - two correlated groups
one dependent variable - rank-ordered data

3

Kurskal-Wallis Test

one independent variable - two or more independent groups
one dependent variable - rank-ordered data

4

Mann-Whitney is the nonparametric version of ______

the t-test for independent samples

5

Wilcoxon is the nonparametric version of ________

the t-test for correlated samples

6

Kurskal-Wallis is the nonparametric version of ________

the one-way ANOVA

7

Parametric tests are measured on _____ & _____ scales.

interval & ratio

8

Nonparametric tests are measured on _______ & _______ scales.

nominal & ordinal

9

Type I error

investigator rejects a true null hypothesis

10

Type II error

investigator fails to reject a false null hypothesis

11

3 predictions of the Central Limit Theorem

regardless of the shape of the distribution of individual scores in the population, as the sample size increases, the sampling distribution of the mean approaches a normal distribution

mean of the sampling distribution of the mean is equal to the population mean

standard deviation of the sampling distribution of the mean is equal to the population standard deviation divided by the square root of the sample size

12

formula for standard error of the mean

SEM = standard deviation / square root of N

13

variance

standard deviation squared

14

percentage of scores within one standard deviation

68

15

percentage of scores within two standard deviations

95

16

percentage of scores within three standard deviations

99

17

t-test

used to compare only two means at a time

a study including more than two means (more than two levels of the IV) would require multiple t-tests and would increase experimentwise error rate

18

ANOVA

used to compare two or more means

simultaneously makes all comparisons while holding the probability of making a Type I error at the level of significance set by the experimenter

19

one-way ANOVA

used when a study includes one independent variable

20

factorial ANOVA

used when a study includes two or more independent variables

21

Cohen's d

measure of the difference between tow groups in terms of standard deviation units

small effect size = 0.2
medium effect size = 0.5
large effect size = 0.8

22

Eta squared

indicates the percent of variance in the outcome variable that is accounted for by variance in the treatment

23

Pearson r

data on both variables represents a continuous scale (interval or ratio data)

24

Spearman rho

both variables are ranks

25

Point biserial

one variable is a true dichotomy and the other is continuous

26

Biserial

one variable is an artificial dichotomy and the other is continuous

27

eta

the variables are both continuous and have a nonlinear relationship

28

external validity

the degree to which a study's results can be generalized to other people, settings, conditions, etc.

29

internal validity

the degree to which a study allows an investigator to conclude that observed variability in a dependent variable is due to the independent variable rather than to other factors

30

moderator variables

affect the strength or direction of the relationship between independent and dependent variables

if a treatment works better for men than for women, gender is a moderator variable

31

mediator variables

explain the relationship between independent and dependent variables

a parenting style might lead to better school performance because it leads to more self efficacy beliefs. so self-efficacy beliefs are the mediator in the relationship between parenting style and school performance