stats

Question 1

what are parametric tests and what do they typically assume

Answer 1

statistical tests that make certain assumptions about the underlying population distribution of the data
- follows a normal distribution
- equal variance across groups
- measured on an interval or ratio scale

Question 2

define dependent variable

Answer 2

data your participants provide, and variable you measure
-e.g reaction times, score on a test etc

Question 3

whats the independent variable

Answer 3

the variable you manipulate (change), the conditions or groups that are compared, either by comparing diff groups or stimuli

Question 4

when is an independent samples test used

Answer 4

when comparing the means of two groups that are independent of each other
- meaning observations in one group do not influence those in the other group

Question 5

when is a repeated measures design used

Answer 5

when participants are exposed to more than one condition, and their responses are measured multiple times
- used to observe how participants behaviour or performance chnages over time or under different conditions

Question 6

what do inferential tests (t-test and ANOVA) check

Answer 6

how likely it is that the results from the different conditions in your experiment came from the same population

Question 7

what do you say/do when the inferential test(s) are highly unlikely that they came from the same population

Answer 7

• usually due to difference between conditions in experimental manipulation
• say the difference is statistically significant
• if likely results from condition came from same population then we CANNOT conclude the independent variable had an effect
• say the difference between conditions is non-significant

Question 8

what does null hypothesis mean

Answer 8

there is no different between your conditions, they were sampled from the same population

Question 9

whats an experimental hypothesis

Answer 9

there is a difference between conditions, the conditions were sampled from different populations

Question 10

whats the difference between a one tailed and two tailed hypothesis

Answer 10

• 1: tests for effect in one specific direction
• 2: tests for an effect in both direction (greater or smaller)

Question 11

when can H0 be rejected and not rejected

Answer 11

can be rejected if p< .05 and we accept the H1
- cannot be rejected if p> .05

Question 12

what does it mean if p= .05 and what do you conclude and what is this known as

Answer 12

there is a 5% chance its a false positive, and conclude that samples came from different populations even if they did not
- knows as a Type I error

Question 13

what is possible if p> .05

Answer 13

may be a false negative, and do not reject H0, even though the samples came from different populations
- type II error

Question 14

whats a type I error

Answer 14

a false positive
- when we incoreectly reject the null hypothesis
- rejecting it when its actually true

Question 15

whats a type II error

Answer 15

false negative
- we fail to reject the null hypothesis
- its actually false (missing a real effect or difference)

Question 16

in a parametric assumption what should the dependant variable either be

Answer 16

a measurement or scale variable

Question 17

when is a one sample t test used

Answer 17

when you want to compare the mean of a single sample to a known value
- used to determine whether the sample mean significantly differs from the reference value

Question 18

when do you use an independant samples t test

Answer 18

for comparing unrealted groups
- e.g different individuals in each group
- 2 conditions

Question 19

when do you use a paired samples t test

Answer 19

for comparing related groups or repeated measurements on the same individuals
- 2 conditions

Question 20

when do you use a oneway independent measures ANOVA test

Answer 20

• 3 or more conditions
• independent

Question 21

when do you use a one-way repeated measures ANOVA

Answer 21

• 3 or more conditions
• repeated experiment

Question 22

when do you use ANOVA for results

Answer 22

when you have more than two conditions

Question 23

how do you check if two conditions differ in ANOVA

Answer 23

pairwise comparisons

Question 24

what is a post hoc pairwise comparison and how is it carried out

Answer 24

• conducted after ANOVA
• helps identify which specific groups differ from each other
• Tukey’s HSD
• Bonferroni Correction

Question 25

what are 2 non- parmetric tests

Answer 25

• mann whitney U test and Wilcoxon

Question 26

when are non- parametric tests used

Answer 26

• when data does not meet the assumptions of parametric tests
• or when sample size is too small to accurately assess the distribution

Question 27

whats the alternative to an independent samples t-test

Answer 27

Mann Whitney U test

Question 28

whats the alternative to the paired t- test

Answer 28

wilcoxon test