RESEARCH METHODS - Descriptive statistics: overview and requency distribution

Question 1

Define: descriptive statistics

Answer 1

used by researchers to organise, summarise and (describe) data collected from a research study so data can be interpreted more easily

Question 2

3 types of descriptive statistics?

Answer 2

Frequency distribution, measures of central tendency, measures of variability

Question 3

Define: frequency distribution

Answer 3

A way of organising data to show how often a value occurs in a set of data

Question 4

How is frequency distribution presented?

Answer 4

In a table, histogram and frequency polygon

Question 5

Define: normal distribution

Answer 5

a graph with a bell-shaped pattern showing the largest number of scores around the middle, tapering to very few extremely high or extremely low scores on either side of the average

Question 6

The normal distribution curve is a ___________ _____ but is ______ _________.

Answer 6

theoretical ideal; rarely achieved

Question 7

Define: positively skewed distribution

Answer 7

Clustering of scores towards the LEFT END of the graph where the scores are the LOWEST

Question 8

Define: negatively skewed distribution:

Answer 8

Clustering of scores towards the RIGHT END of the graph where the scores are the HIGHEST

Question 9

Define: bimodal distribution

Answer 9

When two particular scores occur equally often

Question 10

Provide an example of normal, positively skewed, negatively skewed and bimodal distribution

Answer 10

Normal: number of driving lessons needed to get licence
Positively skewed: number of words spoken at 6 months
Negatively skewed: number of words spoken at 16 years
Bimodal: scores obtained on an English vocab test for people who have spoken english all their lives vs immigrants

Question 11

Define: central tendency

Answer 11

A descriptive statistic used to show the average value of a set of scores

Question 12

Describe: mean, median and mode

Answer 12

Mean: average
Median: midpoint of a set of scores
Mode: most frequently occuring value

Question 13

When is the mean useful and not useful?

Answer 13

Useful if scores cluster around the central score; but misleading if scores are skewed

Question 14

When is the median useful and not useful?

Answer 14

Useful when there are extreme scores, but time consuming/impractical if there are many scores

Question 15

When is the mode useful and not useful?

Answer 15

Useful to indicate most common value but otherwise fucking useless.