Presenting Data Flashcards
Why are diagrams used to represent data?
A lot of people find it easier to visualise information in a diagram.
How do you work out the size of the radius on a comparative pie chart?
- Choose a radius for the first pie chart.
- Work out the area of the first pie chart.
- Work out the scale factor by using the total frequencies.(2nd pie chart frequency / 1st pie chart frequency)
- Use this to work out the area of the 2nd pie chart.(step 3 fraction x 1st pie chart area).
- Divide by pi and square root step 4 to find the radius.
For data that is grouped, how are the bars in a bar chart set out?
Without any gaps.
What is a frequency diagram?
A bar chart representing grouped data.
When is a cumulative frequency diagram used?
When data is continuous.
What is the formula for working out the frequency density?
frequency density = frequency / class width.
What is a bimodal distribution?
A distribution that happens to have two modes.
When should a bar chart be used?
When the data is qualitative or discrete.
When should a line graph be used?
When the data is continuous; generally when the horizontal axis is time.
What are anomalies?
Points on a graph that do not fit the general trend.
What is a population pyramid used for?
To compare the age distribution of two parts of a population.
What might make a graph misleading?
- If the scale doesn’t start at zero, which will make changes seem greater than they actually are.
- If a scale goes up by different amounts; if it is not linear.
- If areas/volumes are not in proportion; if widths and heights are used as a proportion instead.
When should a vertical line graph be used?
When the data is qualitative or discrete.
When should a pictogram be used?
When the data is qualitative or discrete.
When should a pie chart be used?
When the data is qualitative or discrete.
