Standardisation and Summarising

Question 1

Summarising the data

Answer 1

Basic summary measures

Nature of variation

measuring of variation

Interpreting the Measures

Question 2

Measures of Location

Answer 2

Representative value of the whole data set

Measure of location

Mean – Average

Median – Line up all the values from smallest to largest then its your middle value

Mode – Most commonly occurring value

Question 3

Data Distribution

Answer 3

Standard deviation – looks at how that data is spread

If we have a standard deviation that’s particularly high then our data is very spread out so it means its less reliable because its spread out so much

Whereas as a smaller standard deviation means that our data is much more compact so any analysis can be more reliable

Symmetrical distribution

Variable skewness – positive skew e.g. (wealth of people) or negative skew

Question 4

Types of Variation

Answer 4

Variability may be divided into two components

Variability due to inherent causes (common cause)

Variability due to special causes (assignable cause)

Question 5

Measuring Variation

Answer 5

Range – complete spread of data

Inter-quartile range – how we can segment our data into the different section

Standard deviation – how spread the data is from the mean

Coefficient of Variation – looks at the proportion of SD

Question 6

Interquartile Range

Answer 6

Upper Quartile =quartile(datarange,3)

Lower Quartile =quartile(datarange,1)

Standard Deviation =STDEVP(datarange)

Relative variation (COV) =(SD/Mean)*100