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Flashcards in Stats Deck (27)
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1
Q

What is a categorical, ordinal and continuous data?

A

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

2
Q

Measure of central tendency

A

Best guess about typical score.

Mode, median and mean.

3
Q

Measures of dispersion

A

Best guess of spread

Range, variance And standard deviation.

4
Q

What is distribution

A

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

5
Q

Characteristics of normal distribution

A

Bell shaped, scores spread evenly around mean,

6
Q

68-95-99.7% rule

A

Most of population will lie within 3 SD from mean

7
Q

What is the confidence interval for

A

With 95% certainty the population mean will lie within

8
Q

What’s a between subjects design

A

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

9
Q

What’s a within subjects design

A

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

10
Q

What’s the P value for

A

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

11
Q

When do you use an independent t-test

A

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

12
Q

When do you use a paired t-test

A

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

13
Q

What’s a percentage overlap

A

If little difference between groups then will overlap

14
Q

What is levens test for

A

If not significant then use equal variance assumed.

15
Q

What is degrees of freedom

A

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

16
Q

What are type 1 and type 11 error

A

Type 1-accept null when it’s true

Type 11-reject null when should accept

17
Q

What is a correlation

A

Relationship between two continuous variables

18
Q

What’s correlation coefficient

A

Strength of relationship Inbetween -1 and 1

19
Q

What is shared variance and equal variance

A

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

20
Q

What is chi squared used for

A

Relationship between two categorical variable.

Makes inferences about likelihood

21
Q

What are the expected and observed values

A

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

22
Q

What are the degrees of freedom for chi squares

A

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

23
Q

What assumptions should be met for chi-squared

A

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

24
Q

What do non parametric tests use

A

Use ranks and less powerful

25
Q

What’s the Shapiro wilk test

A

If not significant then data is normally distributed

26
Q

What non parametric test is used for independent t-test

A

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.

27
Q

Non-parametric for paired t-test

A

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