Data Analysis - Chart Types Flashcards
Describe what a line chart is useful for
Compare different but related data sets
Can display trends
Shows how data values change in relation to a continuous variable (e.g. time)
E.g. how has the sale of a product changed over time?
Describe what a pie chart is useful for
Showing the breakdown of an entity into its component/constituent parts. Each portion represents a static value or category, with the total equalling 100%.
Describe what a bar chart is useful for
Great for comparing related data sets or parts of a whole.
Example: Population numbers of 10 different countries and how they compare to one another
Describe what a stacked bar chart is and what it’s useful for
Like a bar chart, but with each bar divided into sub-bars that are stacked end to end.
Example: Population data for each country split into four age-ranges.
Similar to a column chart, but horizontal.
Describe what a column chart is useful for
Vertical bars to show change over time and compare values side by side.
Example: showing page views vs. user session time on a website as it changes on a month-to-month basis
Similar to a bar chart, but vertical - and not interchangeable with bar charts. For example, a column chart may be better suited for showing negative and positive values.
Describe what a tree map is useful for
Useful for displaying complex hierarchies using nested rectangles.
For example, depicting statewide employment rates within a population over the last year. The size of the rectangle represents the population and the colour represents the employment rate. You can click on a rectangle to drill down into sub-regions.
Describe what a funnel chart is useful for
Displaying a pipeline or different stages of a continuous process.
E.g. sales conversion rate process
Describe what a scatter chart is and what it’s useful for
The circle colors represent the categories of data, and the circle sizes indicate the volume of data. Great for revealing trends, clusters, patterns and correlations between data points.
Example: seeing each product by the number of units sold and the revenue it brings.
Describe what a bubble chart is useful for
A variant of a scatter chart. Useful for comparing a handful of categories to one another in terms of relative significance.
E.g: Understanding areas of significant expenditure in an org’s sales budget
Describe what a sparkline is and what it is useful for
Don’t display an axis but display trends simply and effectively. Great for showing the general trend of a variation.
E.g.: Stock market price fluctuations from opening to closing of a trading day
Describe what a histogram is and what it is useful for
Shows the distribution of data grouped into ‘bins’. Similar but very different to a bar chart - histograms display data distribution, rather than comparing data like a bar chart.
For example, grouping car models into their pricing bands such as number of models priced £10,000-£15,000 - number of models prices £15,000-20,000 and so on.
What is a numpy arrary or ndarray?
Similar to a python list. Usually fixed in size with each element the same type (e.g. int or string)
Describe how nested lists are structured within the context of a numpy array?
Each nested list corresponds to a ROW of a numpy array
