Statistics

Question 1

what do inferential statistics allow to?

Answer 1

allow to generalize from the sample to the population, which the sample represents

Question 2

why are inferential statistics crucial?

Answer 2

are crucial because the effects that researchers find in a study may be due to random variability caused by sampling error

Question 3

what are the variables in experimental research?

Answer 3

independent variable and dependent variable

Question 4

what is the independent variable?

Answer 4

The variable that is manipulated (e.g. a treatment).
-> continuous

Question 5

what is the dependent variable?

Answer 5

The variable that is measured (e.g. the outcome of a treatment)
-> Continuous or discrete/categorical

Question 6

what is the relationship between IV and DV?

Answer 6

IV -> DV

Question 7

what is hypothesis testing?

Answer 7

a statistical inference procedure for determining whether a given proposition about a population parameter should be rejected on the basis of observed sample data

Question 8

what is the goal of hypothesis testing?

Answer 8

goal of hypothesis testing is to make inferences about a population based on a sample

Question 9

what is the null hypothesis?

Answer 9

there is no difference in the population(H0)

Question 10

what is it called when you incorrectly reject the null hypothesis?

Answer 10

type I error

Question 11

what is in called when you incorrectly fail to reject the null hypothesis?

Answer 11

type II error

Question 12

what is the alternative hypothesis?

Answer 12

there is a difference in the population (Ha)

Question 13

what are the types of alternative hypotheses?

Answer 13

Directional alternative hypothesis
Non-directional alternative hypothesis

Question 14

what is the Non-directional alternative hypothesis?

Answer 14

The direction of the effect is not determined
Delayed reward leads to either slower or faster learning

Question 15

what is the Directional alternative hypothesis?

Answer 15

The direction of the effect is determined
Delayed reward leads to slower learning

Question 16

what are the potential outcomes of hypothesis testing?

Answer 16

reject the null hypothesis
fail to reject the null hypothesis

Question 17

what does rejecting the null hypothesis not mean?

Answer 17

that the alternative hypothesis is true
* The alternative hypothesis (H1) is never proven true in an absolute sense
* It is only demonstrated that the null hypothesis is very unlikely given the data

Question 18

what does failing to reject the null hypothesis not mean?

Answer 18

This does not mean that the null hypothesis is true but only that evidence against the null hypothesis is not convincing enough to reject it

Question 19

what are the steps for hypothesis testing?

Answer 19

1) state the hypothesis
2) set the criteria for a decision
3) compute the test statistic
4) make a decision

Question 20

what is the level of significance?

Answer 20

refers to a criterion of judgment upon which a decision is made regarding the value stated in a null hypothesis. The criterion is based on the probability of obtaining a statistic measured in a sample if the value stated in the null hypothesis were true.

Question 21

what does the significance level represent?

Answer 21

the maximum acceptable probability of rejecting a true null hypothesis (type I error)

Question 22

what % is the significance level in psychology usually?

Answer 22

5% or 1%

Question 23

The significance level determines how … one is to reject the null-hypothesis

Answer 23

conservative

Question 24

If one has a non-directional hypothesis one needs to carry out a …

Answer 24

two-failed test

Question 25

what is the test statistic?

Answer 25

is a mathematical formula that allows researchers to determine the likelihood of obtaining sample outcomes if the null hypothesis were true

Question 26

what is the value of a test statistic used for?

Answer 26

to make a decision regarding the null hypothesis

Question 27

what is the decision based on?

Answer 27

the probability of obtaining a sample mean, given that the value stated in the null hypothesis is true

Question 28

what is the decision when the probability of obtaining a sample mean is less than the significance level?

Answer 28

decision is to reject the null hypothesis

Question 29

what is the decision when the probability of obtaining a sample mean is greater than the significance level?

Answer 29

decision is to retain the null hypothesis

Question 30

(1- α)

Answer 30

The decision to retain the null hypothesis could be correct

Question 31

(α)

Answer 31

The decision to reject the null hypothesis could be incorrect

Question 32

(β)

Answer 32

The decision to retain the null hypothesis could be incorrect

Question 33

(1- β)

Answer 33

The decision to reject the null hypothesis could be correct

Question 34

which error is it when the decision to reject the null hypothesis could be incorrect

Answer 34

type I error (α)

Question 35

which error is it when the decision to retain the null hypothesis could be incorrect

Answer 35

type II error (β)

Question 36

what is type I error?

Answer 36

probability of rejecting a null hypothesis that is actually true

Question 37

what are the consequences of type I error?

Answer 37

Type I can be bad, because it might mislead researchers to believe that a manipulation or treatment is effective while in fact it is not

Question 38

what is type II error?

Answer 38

the probability of retaining a false null hypothesis

Question 39

what are the consequences of type II error?

Answer 39

Type II may not be so bad, if it is understood that the manipulation or treatment may still have an effect (we fail to reject the null hypothesis, but we do not reject the alternative hypothesis)

Question 40

what is the power in hypothesis testing?

Answer 40

the probability of rejecting a false null hypothesis

Question 41

what is (1-ß)?

Answer 41

statistical power

Question 42

what is the power of a hypothesis test denied as?

Answer 42

the probability that the test will reject the null hypothesis when the treatment does have an effect (rule of thumb: minimum of 80%)

Question 43

what does statistical power depend on?

Answer 43

effect size alpha level sample size

Question 44

which effect size means more power?

Answer 44

larger effect size

Question 45

which alpa level means more power?

Answer 45

liberal alpha level

Question 46

which sample size means more power?

Answer 46

larger sample size