Introduction to statistical reasoning

Question 1

research process

Answer 1

• initial observation
• generate theory
• generate hypotheses
• collect data to test theory
• analyse data

kijken naar figuur en overtekenen nog!!! in schrift, pen was op (studentwiki, lecture 2)

Question 2

independent variable =

Answer 2

a variable that is thought to be the cause of some effect (experimenter manipulates this)

Question 3

dependent variable =

Answer 3

a variable that is thought to be affected by changes of the independent variable (outcome)

Question 4

predictor variable =

Answer 4

a variable that is thought to predict an outcome variable (een independent variable is een van de predictor variables)

Question 5

level of measurement: 2 types

Answer 5

categorical and numerical

Question 6

categorical =

Answer 6

qualitative: divided into distinct categorieso

Question 7

voorbeelden categorical

Answer 7

• binary
• nominal (more than two categories, not in order)
• ordinal (categories in order)

Question 8

numerical =

Answer 8

quantitative, echt alleen nummers

Question 9

continous voorbeelden

Answer 9

• interval (equal intervals represent equal differences)
• ratio (ratios also make sense: een score van 16 op anxiety scale is dubbel zoveel anxiety als iemand met score van 8). scale must have a meaningful zero point for this!!!

Question 10

wat voor measurement is likert variable

Answer 10

ordinal

Question 11

oke dus measurement levels de eerste

Answer 11

categorical (qualitative) & numerical (quantitative)

Question 12

soorten categorical =

Answer 12

nominal (geen order) en ordinal (wel order)

Question 13

soorten numerical =

Answer 13

• discrete (steps, only particular numbers)
• continuous (kunnen alle nummers zijn)

Question 14

soorten discrete

Answer 14

• nominal (nummers voor classification purposes: dus 0 voor man, 1 voor vrouw)
• ordinal (heeft een waarde: 1 voor lage SES, 2 voor middel SES etc)

Question 15

soorten continous=

Answer 15

• interval
• ratio (met zero point, 2x zoveel score is 2x zo veel effect)

Interval variable: Equal intervals on the variable represent equal
differences in the property being measured (e.g., the difference between 6 and 8 is equivalent to the difference between 13 and 15).

Ratio variable: The same as an interval variable, but the ratios of scores on the scale must also make sense (e.g., a score of 16 on ananxiety scale means that the person is, in reality, twice as anxious as someone scoring 8). For this to be true, the scale must have a meaningful zero point.

Question 16

measurement error=

Answer 16

discrepancy between the thing we are measurng and the actual value of the thing we are measuring

Question 17

criterion validity =

Answer 17

evidence that scores from an instrument correspond with (concurrent validity) or predict (predictive validity) external measures conceptually related to the measured construct

dus is het gelijk aan de criterion van andere testen?

Question 18

concurrent validity=

Answer 18

a form of criterion validity where there is evidence that scores from an instrument
correspond to concurrently recorded external measures conceptually related to the
measured construct

Question 19

content validity=

Answer 19

does the content of the test correspond to the content it was designed to cover?

Question 20

predictive validity =

Answer 20

a form of criterion validity where there is evidence that scores from an instrument
predict external measures (recorded at a different point in time) conceptually related
to the measured construct.

Question 21

dus twee vormen van criterion validity=

Answer 21

predictive & concurrent validity

Question 22

reliability =

Answer 22

zijn de resultaten repliceerbaar? hoeveel measurement errors en noise is opgetreden?

Question 23

test-retest reliability =

Answer 23

will the same group of people tested twice get the same results?

Question 24

david hume said to infer cause and effect…

Answer 24

• cause and effect should occur close in time: continuity
• cause must occur before the effect does: priority
• the effect should never occur without the presence of the cause: exclusivity

Question 25

tertium quid problem=

Answer 25

an unidentified third element that is in combination with two known ones. ook wel confounding

Question 26

wat heeft john stuart mill er door confounding variables bij gezegd

Answer 26

dat causality alleen infered kan worden through comparison of two controlled situations: one in which the cause is present and one in which the cause is absent (=experiment)

Question 27

two methods of data collection

Answer 27

between-groups/between subjects/independent design within-subject/repeated measures

Question 28

two types of variation

Answer 28

unsystemic: random factors that exist between the experimental conditions systemic: when the experimenter does something in one condition but not in the other

Question 29

2 sources of systematic variation in experiments

Answer 29

- practice effects - boredom effects (tired/bored)

Question 30

hoe kan je deze systematic variation tegengaan

Answer 30

door counterbalancing the order in which a person participates in a condition

Question 31

5 statistics of a quantitative variable

Answer 31

1. mean 2. standard deviation 3. skewness (direction and degree) 4. kurtosis: thickness of the tails 5. z scores

Question 32

frequency distribution ander woord

Answer 32

histogram

Question 33

2 ways in which a graph can deviate from a normal distribution

Answer 33

1. skew (lack of symmetry) 2. pointiness (kurtosis)

Question 34

hoe interpreteer je skew

Answer 34

hoe dichter bij de nul, hoe kleiner de skew. hoe verder weg (negatief of positief), hoe meer geskewed

Question 35

hoe heet een distribution met positive kurtosis en wat is het

Answer 35

leptokurtic distribution: veel scores in de tails.

Question 36

hoe heet een distribution met negative kurtosis en wat is het

Answer 36

platykurtic: dun in de tails, flatter than normal

Question 37

hoe heet een normale kurtosis

Answer 37

mesokurtic

Question 38

hoe de kurtosis interpreteren

Answer 38

alleen positieve getallen. > 2 is high positive 1-2 moderate positive 0.5-1 weak positive 0-0.5 zero kurtosis

Question 39

mode=

Answer 39

the score that occurs most frequently

Question 40

hoe heet het als meerdere getallen het vaakste voorkomen

Answer 40

bimodel = 2 getallen multimodel = meerdere getallen

Question 41

median =

Answer 41

the middle score, when scores are ranked in order of magnitude

Question 42

disadvantage of the mean

Answer 42

- can be influenced by extreme scores - can be influenced by skewed distributions - only with interval or ratio data

Question 43

advantage of the mean, tov median en mode

Answer 43

-de mean gebruikt alle getallen ipv focussen op 1 -mean tends to be stable in different samples

Question 44

range disadvantage

Answer 44

extremely easily influenced by extremes

Question 45

hoe fix je dat de range zo beinvloedt wordt door extreme scores

Answer 45

interquartile range gebruiken. -> split the data into four equal parts. median = second quartile