Chapter 15 Athena en lecture

Question 1

central question of hypothesis testing

Answer 1

how extreme is a sample if the null hypothesis is true?

Question 2

test statistic

Answer 2

a standardized measure of how far the point estimate falls from the parameter value if the null hypothesis is true

Question 3

sampling distribution

Answer 3

a probability distribution that specifies probabilities for the possible values the statistic can take

Question 4

central limit theorem

Answer 4

for any large enough sample, the sampling distribution is approximately normally distributed with
mean = u
stdev = o/wortel(n)

Question 5

wilcoxon test assumpties

Answer 5

• data are ranked ordered
• two independent samples
• (no assumption about distribution)

Question 6

wat is H0 bij wilcoxon test

Answer 6

H0=the population distributions of the quantitative score are identical

Question 7

wat is Ha bij wilcoxon test

Answer 7

Ha= the population distributions of the quantitative score differ in such a way that the expected average ranks are also different

Question 8

test statistic bij wilcoxon test

Answer 8

= difference in average of all ranks in that group/condition

Question 9

wat is de p bij wilcoxon test

Answer 9

altijd two sided! dus x2

Question 10

ranks berekenen

Answer 10

alles in een grote kolom
dan ranks invullen (GOED TELLEN: kom je uit op totale n? en alle ties goed?)
dan gemiddelde van alle ranks terwijl ze in de rij staan!!
dan terug zetten in kolommen
dan Ri berekenen per groep

Question 11

hoe de pvalue berekenen bij kruskal wallis test

Answer 11

1-chi.dist
met df= g-1

Question 12

wanner sign test gebruiken

Answer 12

bij two dependent groups (als niet normaal verdeeld is)

Question 13

wat is het principe van de sign test

Answer 13

+ en - bij pretest post test!

posttest-pretest

Question 14

wat als het 0 is bij de sign test

Answer 14

? invullen

Question 15

assumpties van sign test

Answer 15

random samples of matched pairs, unequal values for each pair

Question 16

wat is belangrijk bij de sign test qua hypothese?

Answer 16

als het one sided is: goed kijken of de hypothese is pretest>post test of andersom!

dan op basis daarvan de formule doen. + = GOEDE UITKOMST

Question 17

wat is H0 bij sign test

Answer 17

H0= the samples contain independent pairs, p op + = 0,5

Question 18

wat is de test statistic bij sign test

Answer 18

hoeveel mensen een + hadden

Question 19

wat voor soort variabele bij non-parametric tests

Answer 19

ordinal!!

Question 20

wanneer nonparametric tests gebruiken

Answer 20

We do not know whether the data are normally distributed (e.g.,
because of small sample size)
The data are not normally distributed and sample size is too low for
the central limit theorem to apply

Question 21

waar wordt elk van de 3 testen voor gebruikt

Answer 21

• wilcoxon: two independent groups
• kruskal wallis: more than two independent groups
• sign test: two dependent groups

Question 22

wilcoxon test stappen

Answer 22

When conducting Wilcoxon test:
Convert to ranks (remember the Excel tip!)
Calculate the mean rank per group
Calculate the difference between mean ranks
Locate the difference in the sampling distribution
Small n→ look at the sample space, then construct sampling distribution
(construction of sampling distribution not needed for exam)
Large n→ normal approximation

Question 23

kruskal wallis test stappen

Answer 23

When conducting Kruskal-Wallis test:
Convert to ranks (remember the Excel tip!)
Calculate the appropriate statistics (overall mean rank, mean rank per
group)
Fill in the formula for the test statistic
Locate the test statistic in the Chi Square distribution (df = #groups -1)

Question 24

sign test stappen

Answer 24

When conducting sign test:
Compute the difference scores
Count the number of positive difference scores
Locate the test statistic in the sampling distribution
For n ≥ 30 → normal approximation
For smaller n→ binomial distribution

Question 25

parametric testing

Answer 25

Parametric
* More assumptions
* Sensitive to outliers
* Preferred when much data
* More power
* Also applicable to more
complex models

Question 26

nonparametric testing

Answer 26

Non-parametric
* Less assumptions
* Less sensitive to outliers
* Preferred when data is limited
* Less power
* Not as well-developed for more
complex models

Question 27

waar zijn rank analyses tegen bestemd

Answer 27

outliers!

Question 28

hoe p value berekenen bij de wilcoxon test

Answer 28

aflezen uit sampling distribution.
difference in mean ranks gebriuken: kijken naar deze value of meer extreem.

stel difference = 2, dan P= 2* (P(2)+P(3)+P(4)… etc.

of z score gebruiken (zie formule blad)

Question 29

GOED KIJKEN NAAR OF HET ONE SIDED OF TWO SIDED IS!! ANDERS P VALUE ALTIJD *2!!!!!

Answer 29

OKE