1.8 - Analysing data

Question 1

What does a histogram show us?

Answer 1

How many times each score occurs

Question 2

What is the y-axis on a histogram?

Answer 2

Frequency

Question 3

Why are histograms useful?

Answer 3

Can assess properties of the distribution of scores

Question 4

What are 3 characteristics of a normal distribution?

Answer 4

Symmetrical across the mean
Bell-shaped curve
Tails touch infinity line either side

Question 5

What are 2 ways in which distributions can deviate from normal?

Answer 5

Skew

Kurtosis

Question 6

What types of skew are there?

Answer 6

Positive

Negative

Question 7

What does a positively skewed graph look like?

Answer 7

Tails end at the positive end of the scale

Question 8

What does a negatively skewed graph look like?

Answer 8

Tails end at the lower end of the scale

Question 9

What does skew mean?

Answer 9

Lack of symmetry

Most frequent scores are clustered at one end of the scale

Question 10

What is kurtosis?

Answer 10

Refers to the pointiness of the graph

Question 11

What are 3 types of kurtosis?

Answer 11

Leptokurtic
Mesokurtic
Platykurtic

Question 12

What does a platykurtic graph look like?

Answer 12

Flat distribution
Thin tailed
Negative kurtosis

Question 13

What does a leptokurtic graph look like?

Answer 13

Pointy
Heavy tailed
Positive kurtosis

Question 14

What does a mesokurtic graph look like?

Answer 14

Relatively normal distribution

Question 15

What are 3 common measures of central tendency?

Answer 15

Mean
Median
Mode

Question 16

What is the mode?

Answer 16

The score that occurs most frequently in a data set

Question 17

How do you spot the mode on a histogram?

Answer 17

Tallest bar

Question 18

What does bimodal mean?

Answer 18

Distribution with 2 modes

Question 19

What does multimodal mean?

Answer 19

Data sets with more than 2 modes

Question 20

What is the median?

Answer 20

The middle score when ranked in order

Question 21

What data can median be used for?

Answer 21

Ordinal

Also interval and ratio

Question 22

What data can the mode be used on?

Answer 22

Nominal

All types

Question 23

What is the mean?

Answer 23

Average of scores

Question 24

What is a disadvantage of the mean?

Answer 24

Influenced by extreme scores and affected by skewed distributions

Question 25

What data can the mean be used on?

Answer 25

Interval and ratio

Question 26

What are quartiles?

Answer 26

3 values that split the data into equal quarters

Question 27

What are the 3 quartiles?

Answer 27

1st - lower quartile 2nd - median 3rd - upper quartile

Question 28

How do we calculate the interquartile range?

Answer 28

Upper - lower

Question 29

Advantage of interquartile range

Answer 29

Not affected by extreme scores

Question 30

Disadvantage of interquartile range

Answer 30

Lose a lot of data

Question 31

How do we calculate deviance?

Answer 31

individual score - mean score

Question 32

How do we calculate sum of squared errors?

Answer 32

Square all deviances and add up

Question 33

Why do we square the deviances?

Answer 33

To avoid getting zero or negative numbers as our answer

Question 34

What is the problem with using SS?

Answer 34

Can't compare the total of dispersion to other samples that differ in size

Question 35

How do we calculate the average dispersion (variance)?

Answer 35

Divide SS by degrees of freedom (n-1)

Question 36

How do we get the standard deviation from variance?

Answer 36

Square root the variance

Question 37

What are 3 measures of dispersion?

Answer 37

Sum of squares Standard deviation Variance

Question 38

What would a standard deviation of 0 indicate?

Answer 38

That all the results are the same

Question 39

Is a large or small standard deviation ideal?

Answer 39

The smaller the standard deviation score, the more accurate the data is to the mean