Descriptive statistics

Question 1

What are descriptive statistics?

Answer 1

• mathematical summaries of the data set
• brief insight into the overall results of a study and how likely it is to be reliable

Question 2

Give 2 types of descriptive statistics.

Answer 2

• measures of central tendency
• measures of dispersion

Question 3

What are measures of central tendency?

Answer 3

-mean: add numbers then divide by amount of numbers
-median: middle number
-mode: most common number

Question 4

STRENGTHS/WEAKNESSES of mean

Answer 4

STRENGTHS
-takes into account all scores
WEAKNESSES
-easily distorted by anomalies
-cannot be used with nominal data

Question 5

STRENGTHS/WEAKNESSES of median

Answer 5

STRENGTHS
- not influenced by anomalies
- can be found using ordinal data
WEAKNESSES
- not all values are considered

Question 6

STREGTHS/WEAKNESSES of mode

Answer 6

STRENGTHS
- can be used for nominal data
- not affected by anomalies
WEAKNESSES
- unreliable with small data sets

Question 7

What are the measures of dispersion

Answer 7

-range: highest minus lowest
-standard deviation: how far the majority of the results are from the mean

Question 8

STRENGTHS/WEAKNESSES of range

Answer 8

STRENGTHS
-easy to calculate
WEAKNESSES
-only takes into account extreme values (unrepresentative)

Question 9

STRENGTHS/WEAKNESSES of standard deviation

Answer 9

STRENGTHS
-takes all values into account
-precise measure of dispersion
WEAKNESSES
-more difficult to calculate
-may get distorted by anomalies

Question 10

How is standard deviation calculated?

Answer 10

1) calculate the mean of the data set (when dividing the sum by the amount of numbers subtract 1 from the amount of numbers)
2) subtract the mean from each data point
3) square each difference
4)calculate the mean of the squared differences
5) square root the answer