data visualisation

Question 1

why do we plot data

Answer 1

visualise it

understand it

communicate it

Question 2

what does a frequency table show

Answer 2

• overview of all responses
• min and max
• mode
• identify outliers
• nominal or sometimes ordinal data

shows the frequency of each case of a particular variable

Question 3

what does a frequency histogram show

Answer 3

they are for numerical data, particularly interval level data

• allows you to see shape and distribution of interval data
• see outliers

Question 4

what is a frequency polygon

Answer 4

same information as a frequency histogram, just with a different look

solid shape rather than bars

Question 5

what does a bar chart show

Answer 5

represent a summary of stats for categorical data

summary stat could be a mean, total, percentage - any way of summarising a group of categorical values/experimental conditions

Question 6

how to create a bar chart

Answer 6

categorical data (variables) on x axis and value for each category on y axis

Question 7

data points underlying averages

Answer 7

might be best to show the data points underlying comparisons of means

this can reveal bias due to skewness, floor effects or outliers

Question 8

what does a line graph show

Answer 8

-differences in mean, frequency, or proportion are plotted on the y axis

time or a different value plotted on x axis

good for illustrating trends over time

good for illustrating multiple trends simultaneously

Question 9

what does a data table often show

Answer 9

often shows descriptive statistics

Question 10

pie chart

Answer 10

differences in proportion are plotted as radial segments of a circle

popular but less easy to read, 3D pic charts even more so