Inferential Statistics

Question 1

What do inferential statistics do?

Answer 1

they make inferences (conclusions) about the population

Question 2

what are the 2 types of inferential statistics?

Answer 2

Frequentist (uses sample data to draw conclusions by empathising frequency / probability)
Bayes

Question 3

What are the 4 features of frequentist inferential statistics?

Answer 3

Null hypothesis significance testing
P-values
Effect size
confidence intervals

Question 4

What is Null hypothesis significance testing (NHST)?

Answer 4

when an experimental factor is tested against a hypothesis of no effect or relationship

Question 5

Null Hypothesis is H_?

Answer 5

H0
no difference

Question 6

Alternative Hypothesis is H_?

Answer 6

H1
difference
has 2 types

Question 7

what are the 2 types of Alternative (experimental) hypothesis?

Answer 7

Directional (one tailed)
Non-directional (two tailed)

Question 8

What is the P-value rule?

Answer 8

if p-value is below 0.05 then result is ‘statistically significant’
the level we accept results is also known as ‘alpha level’
can use 1% to be stricter

Question 9

How do P-values work in frequentist inferential statistics?

Answer 9

probability result found occurred by chance assuming null hypothesis is true
tells us if there’s false-positives

Question 10

what does it mean if the p-value is high?

Answer 10

more likely results are ‘statistically non-significant’

Question 11

How do you write up a p-value that’s written as e-16 (for example)?

Answer 11

means p-value is really small
p<.001

Question 12

What are Effect Sizes?

Answer 12

tell us about the magnitude of the difference or similarity of a correlation

Question 13

What is the most popular effect size?

Answer 13

Cohen’s d (measures size of difference between groups)
Pearsons r (measures strength of relationship between 2 variables)

Question 14

When is cohen’s d often used?

Answer 14

often used in independent samples t-tests
continues data with large samples

Question 15

Chi Square

Answer 15

used to discover if there is a relationship between 2 categorical (nominal) or sometimes ordinal variables

Question 16

What can Chi Square only be used for?

Answer 16

only be used for a between subjects design
groups must be independent

Question 17

what is the symbol for Chi Square

Answer 17

χ2
symbol comprised of small greek letter chi and 2 superscript

Question 18

How to calculate expected frequencies

Answer 18

Row total x column total divided by total N
N = no. of ppts
Values taken from observed frequencies table

Question 19

What does Chi square measure?

Answer 19

the difference between observed frequencies and expected frequencies
if they differ then suggested there’s an association between IV and DV

Question 20

What is it called when Chi Square table has 2 rows and 2 columns?

Answer 20

Chi square that’s conducted will be known as 2x2 chi square

Question 21

what is the goodness of fit test?

Answer 21

statistical hypothesis used to see how closely observed data mirrors expected data