descriptive stats

Question 1

mean

Answer 1

total of all values in a set of data is divided by the number of values

• makes use of all values
• good for interval data
• influenced by outliers so can be unrepresentative

Question 2

median

Answer 2

arrange data from lowest to highest then find the central value

• not affected by extreme scores
• good for ordinal data
• not as sensitive as mean, does not use all data

Question 3

mode

Answer 3

most frequently occurring value in a set of data

• useful for nominal data
• not useful when there are several modes

Question 4

range

Answer 4

minus the lowest score from the highest score

• easy to calculate
• affected by extreme values
• does not use all data

Question 5

statistical deviation

Answer 5

the square root of the variance calculates SD - low measure data closer

• precise measure where all data values are taken into account
• difficult to calculate
• affected by extreme values

Question 6

bar chart

Answer 6

• discrete data - data divided into categories
• do not touch so shows we are dealing with separate conditions

Question 7

histograms

Answer 7

bars touch as dealing with continuous data

Question 8

line graphs

Answer 8

continuous data whereby points are connected by lines to show change of values

Question 9

scattergrams

Answer 9

show associations between co-variables rather than differences

Question 10

normal distribution

Answer 10

a symmetrical pattern of frequency data that forms a bell-shaped pattern

Question 11

skewed distribution

Answer 11

a spread of data that is not symmetrical, instead all cluster to one end

mode - highest point
- median then mean at lowest