RESEARCH METHODS- Descriptive Statistics

Question 1

Measures of Central Tendency

Answer 1

Aim to identify the average/most typical value in a dataset
The mean, median, and mode

Question 2

Mean

Answer 2

The average value of a dataset. ‘x̄’

Question 3

Mean STRENGTHS/WEAKNESSES

Answer 3

S: Highly sensitive; takes ALL values into account
W:Affected by extreme values/outliers, skewing distribution

Question 4

What type of data is mean used for?

Answer 4

Interval/Ratio Data

Question 5

Median

Answer 5

The middle value of a dataset when put into numerical order from smallest–>largest

Question 6

Median STRENGTHS/WEAKNESSES

Answer 6

S: Unaffected by extreme values/outliers
W: Doesn’t take all values into account; not Sensitive

Question 7

What type of data is median used for?

Answer 7

Ordinal Data (commonly)

Question 8

Mode

Answer 8

The most common value found in a dataset
-If there are 2, then it is known as being bimodal

Question 9

Mode STRENGTHS/WEAKNESSES

Answer 9

S:Unaffected by extreme values/outliers + Easy to calculate
W:Doesn’t take all values into account, Not useful for small datasets/those with multiple modes

Question 10

What type of data is mode used for?

Answer 10

Nominal data (commonly)

Question 11

Frequency Tables

Answer 11

Shows how many times a value occurs in a dataset
-Can observe theems/differences

Question 12

Measures of dispersion

Answer 12

Descriptive statistics that aim to identify the spread of scores within a dataset from the measures of central tendency; how VARIED the scores are

Question 13

Range

Answer 13

Explains the range between largest and smallest scores, indicating how spread out the data is

Question 14

Range STRENGTHS/WEAKNESSES

Answer 14

-Easy to calculate (largest value-smallest)
-Affected by extreme scores, so not appropriate for datasets containing outliers
-Doesn’t explain whether scores are bunched or spread around the mean

Question 15

Standard Deviation

Answer 15

Tells the average amount by which each score ‘deviates’ from the mean

Question 16

Standard Deviation STRENGTHS/WEAKNESSES

Answer 16

-Takes all values into account; more precise and sensitive

Question 17

Standard Deviation Equation

Question 18

Bar Charts

Answer 18

-Use nominal data (distinct, operate categories; equal gaps MUST be drawn between bars)
- x-axis labelled with categories of data

Question 19

Histograms

Answer 19

-Use interval/ratio data (continuous scale; NO gaps drawn)
- x-axis labelled with the scale/range of data

Question 20

Distribution (DEFINITION)

Answer 20

Describes how the data is spread out

Question 21

Normal Distribution

Answer 21

The graph is symmetrical, with mean=median=mode

Question 22

Positively Skewed Distribution

Answer 22

Data is skewed to the right- long tail to the right
Mode<Median<Mean

Question 23

Negatively Skewed Distribution

Answer 23

Data is skewed to the left- long tail to the left
Mode>Median>Mean

Question 24

Low SD indicates…

Answer 24

Consistency in scores. all bunched close together around the mean

Question 25

High SD indicates...

Answer 25

Where scores are spread our around the mean- usually meaning that the behaviour being studied is NOT affected by the IV