DESCRIPTIVE STATISTICS: MEASURES OF CENTRAL TENDENCY AND DISPERSION AO1 & AO3

Question 1

Mode + EVA

Answer 1

• Most common or most frequent value (used with nominal data)

+ Easy to calculate
+ Can be used with nominal data
- Doesn’t tell us anything except which thing happens most
- Multimodel distributions can be uninformative

Question 2

Median + EVA

Answer 2

Middle number when data is in rank order (usually ordinal data)

+ Relatively easy to calculate
+ Not affected by extreme values (so useful for interval data with extreme values)

-Lacks sensitivity when compared to the mean – this is because it doesn’t take actual values into account

Question 3

Mean + EVA

Answer 3

The arithmetic average – ass up all the individual scores and divide by the number of scores you have

+Takes into account each actual value
+The most sensitive measure of central tendency
-Influenced by extreme values
-More complex to calculate than other measures

Question 4

Measures of dispersion (spread)

Answer 4

Range
Standard deviation

Question 5

Range

Answer 5

The difference between the highest and lowest values

+ Easy to calculate
- Affected by extreme values

Question 6

Standard Deviation + EVA

Answer 6

The average distribution that each piece of data is from the mean for the group

+ Takes each piece of data into account so very sensitive
+ Allows us to make predictions about distributions if we know the mean and standard deviation
- Harder and complex calculations