Stats

Question 1

What is a categorical, ordinal and continuous data?

Answer 1

Categorical-each point assigned to category
Ordinal-in logical order but no info about difference eg race scores
Continuous-ranking and scale. Decimal points eg temp

Question 2

Measure of central tendency

Answer 2

Best guess about typical score.

Mode, median and mean.

Question 3

Measures of dispersion

Answer 3

Best guess of spread

Range, variance And standard deviation.

Question 4

What is distribution

Answer 4

How the typical value and spread of scores relate to each other

Question 5

Characteristics of normal distribution

Answer 5

Bell shaped, scores spread evenly around mean,

Question 6

68-95-99.7% rule

Answer 6

Most of population will lie within 3 SD from mean

Question 7

What is the confidence interval for

Answer 7

With 95% certainty the population mean will lie within

Question 8

What’s a between subjects design

Answer 8

Diff Participants take part in diff conditions
No practice or Order effects. Less chance of demand characteristics. But need more participants and have individual differences

Question 9

What’s a within subjects design

Answer 9

Same participants take part in all conditions.
Few participants needed and less individual differences
But practice effects, demand characteristics

Question 10

What’s the P value for

Answer 10

Needs to be less than 0.05 to be significant. It is the probability that we get th same results due to sampling error if null was true

Question 11

When do you use an independent t-test

Answer 11

With a between participants design. Comparing means of 2 independent groups.

Question 12

When do you use a paired t-test

Answer 12

With a within design. Comparing differences between two means of same group

Question 13

What’s a percentage overlap

Answer 13

If little difference between groups then will overlap

Question 14

What is levens test for

Answer 14

If not significant then use equal variance assumed.

Question 15

What is degrees of freedom

Answer 15

The number if scores that are free to vary after final calculation
Independent-n-1+n-1
Correlation n-2

Question 16

What are type 1 and type 11 error

Answer 16

Type 1-accept null when it’s true

Type 11-reject null when should accept

Question 17

What is a correlation

Answer 17

Relationship between two continuous variables

Question 18

What’s correlation coefficient

Answer 18

Strength of relationship Inbetween -1 and 1

Question 19

What is shared variance and equal variance

Answer 19

Shared variance is r squared. And this is the amount of variance that is explained for. Unique variance is any that isn’t explained. The bigger shared the strong the relationship

Question 20

What is chi squared used for

Answer 20

Relationship between two categorical variable.

Makes inferences about likelihood

Question 21

What are the expected and observed values

Answer 21

Expected is what you would presume would be the scores if it was spread out equally. Calculate difference between cells

Question 22

What are the degrees of freedom for chi squares

Answer 22

(Number of columns-1)x(number of rows-1)

Question 23

What assumptions should be met for chi-squared

Answer 23

No more than 25% of cells should have expected value less than 5. And no individual cell should have expected value less than 1

Question 24

What do non parametric tests use

Answer 24

Use ranks and less powerful

Question 25

What’s the Shapiro wilk test

Answer 25

If not significant then data is normally distributed

Question 26

What non parametric test is used for independent t-test

Answer 26

Mann Whitney-compares mean ranks of 2 independent groups.

All scores are ranked and calculates how many times one condition is rated higher than other.

Question 27

Non-parametric for paired t-test

Answer 27

Wilcoxon. Comparing mean ranks of participants who scored higher in on condition than other. Calculate the difference and order and rank. Ignore ties. Separate positives and negatives