Statistics Agresti

Question 1

hypothesis

Answer 1

statement claiming that a population parameter takes a certain value or lies within a particular range of values

Question 2

significance test

Answer 2

summarize the data that is evidence for or against a hypothesis

Question 3

null hypothesis

Answer 3

statements that a population parameter takes a certain value (no effect)

Question 4

alternative hypothesis

Answer 4

statement that a population parameter takes an alternative value

Question 5

test statistic describes…

Answer 5

how far the point estimate falls from the population parameter, given the null hypothesis.

Question 6

p-value

Answer 6

probability that the test statistic equals the observed value or a more extreme value.

Question 7

the p value is calculated presuming that H… is true

Answer 7

H0

Question 8

smaller p values provide stronger evidence…

Answer 8

against the H0

Question 9

H0 is never about …

Answer 9

sample statistics (such as p dakje of x met streepje boven!!!)

Question 10

relatie H0 en Ha alsin hoe je het schrijft

Answer 10

H0 altijd met = teken, Ha is altijd in relatie tot H0.

Question 11

explanatory variable

Answer 11

independent

Question 12

response variable

Answer 12

dependent

Question 13

proportions 2 groups als…

Answer 13

explanatory (indep) = binary, response (dep) = categorical

Question 14

standard error of the difference between sample proportions describes…

Answer 14

the difference in population proportions

Question 15

large enough sample bij proportions

Answer 15

10 successes and 10 failures

Question 16

CI interval for two population proportions

Answer 16

(𝑝̂1− 𝑝̂2) ± 𝑧(𝑠ⅇ)

Question 17

CI interpreteren

Answer 17

• als er een 0 in zit: plausibel dat er geen effect is (verschil tussen de twee groepen = 0)
• als het positief is: p1 > p2
• als het negatief is: p1 < p2

Dus het gaat echt om het verschil tussen de twee groepen! Dus als deze value dicht bij de 1 zit, is er waarschijnlijk een klein verschil.

Question 18

𝑝̂ naam

Answer 18

pooled estimate

Question 19

hoe bereken je de 𝑝̂ voor de se formule van z score

Answer 19

The number of successes in both groups and then dividing this number by the total number of participants used in both groups (𝑛1 + 𝑛2).

total successes/total n

Question 20

wat is de 0 in de formule

Answer 20

de value van de H0!! (H0: p = …)

Question 21

quantitative dependent variable (sigaretten -> bloeddruk)

Answer 21

Based on the difference in sample means, 𝑥1 − 𝑥2, we want to draw conclusions about the difference
in population means, 𝜇1− 𝜇2

Question 22

verschil o, s en se

Answer 22

• o is standard deviation of population,
• s is standard deviation of sample,
• se is the standard deviation of its sampling distribution or an estimate of that standard deviation.

Question 23

wat gebruik je bij quantitative dependent variable

Answer 23

de mean!

Question 24

z score is R/L tail, t score is R/L tail

Answer 24

z = left, t = right

Question 25

CI for mean difference between two groups

Answer 25

(𝑥1 −𝑥2) ± 𝑡.975(𝑠ⅇ)

Question 26

how to calculate the df for means two groups

Answer 26

if 𝑠1= 𝑠2 and 𝑛1= 𝑛2, then 𝑑𝑓 = (𝑛1+ 𝑛2− 2).

Question 27

the degrees of freedom will usually fall between...

Answer 27

(𝑛1+ 𝑛2 – 2), with a minimum of (𝑛1− 1)and (𝑛2− 1)

Question 28

t test is ook robust bij samples kleiner dan 30

Answer 28

oke

Question 29

mean assumptions

Answer 29

qualitative, random, large sample

Question 30

if a two-sided test rejects the null hypothesis of the population being equal, then the confidence interval for the same error probability (e.g. α=0.05 and confidence level is 95%) will not contain 0.

Answer 30

oke

Question 31

dependent samples

Answer 31

within-group design, repeated measures, matched pairs --> when they use the same subjects (even if it is a pair)

Question 32

independent samples

Answer 32

when the observations in one sample are independent from the observations in another sample

Question 33

paired differences

Answer 33

use with matched pairs: calculate xd (score 1 - score2)

Question 34

xd is ook gelijk aan....

Answer 34

the difference between the means of two samples: xd = (x̄1 − x̄2)

Question 35

wat is makkelijk aan dependent samples

Answer 35

het wordt een one sample analysis, want je kan gewoon de scores van elkaar aftrekken.

Question 36

CI voor dependent samples

Answer 36

(xd.) ± 𝑡.975(𝑠ⅇ)

Question 37

z score is ... tail

Answer 37

left

Question 38

hoe bereken je de p value voor =/=

Answer 38

1. eerst z score (formule met wortel) 2. norm.s.dist 3. 1-norm.s.dist 4. 2 * vorige antwoord

Question 39

hoe bereken je de p waarde voor Ha: p < p0

Answer 39

1. z score berekenen: formule met wortel 2. norm.s.dist

Question 40

hoe bereken je de p waarde voor p > p0

Answer 40

1. z score (formule met wortel) 2. norm.s.dist 3. 1-...

Question 41

als je % ziet dan is het....

Answer 41

proportion -> z score!

Question 42

P(type 1 error) =

Answer 42

significance level

Question 43

we do not know if a decision is correct, altijd een kans dat het niet zo is.

Answer 43

oke

Question 44

type 1 error

Answer 44

reject H0 when it is true false positive

Question 45

type 2 error

Answer 45

accept H0 when it is not true, false negative

Question 46

CI is more useful than p value

Answer 46

want bevat alle plausibele waardes; p value laat alleen zien of de H0 plausibel is

Question 47

p-value definitie nog een keer

Answer 47

A p-value measures the probability of obtaining the observed results, assuming that the null hypothesis is true.

Question 48

CI definition

Answer 48

For a 95 % confidence interval, if many samples are collected and the confidence interval computed, in the long run about 95 % of these intervals would contain the true mean.

Question 49

P(type 1 error) decreases if...

Answer 49

- bigger sample size - parameter moves further away from H0, towards Ha.

Question 50

Power =

Answer 50

1-P(type 2 error)

Question 51

3 assumptions t test

Answer 51

Data are quantitative and have been produced randomly and have an approximate normal population distribution.

Question 52

when a p value lies underneith 0,05, does the CI contain the H0?

Answer 52

No, the interval does not contain H0 in 95% CI if it is rejected by the p value