Presentation of quantitative data -charts and graphs Flashcards
When are bar charts used?
When data is divided into categories (dealing with separate conditions)
What does the use of space between bars illustrate?
That the variable on the X axis is not continuous
What are histograms?
They are used for continuous data e.g. weight, height, scores on a test
The bars should touch each other without a gap
Frequency of the values should be on the y axis and continuous values should be places on. the x axis in equal sized intervals
When are scattergrams used?
When you are dealing with a correlation (looking at the relationship between two variables)
What are the two types of distributions and when are they?
When putting data on a histogram the pattern it makes is known as the distribution
the two types are
- Normal
- Skewed
What is a normal distribution?
With a normal distribution, most people or items are located in the middle area of the curve with very few people at the extreme ends. The tails of the curve which extend outwards are more extreme scores
What is a skewed distribution?
A skewed distribution is the one where frequency data is not spread evenly (no symmetrical pattern) the data is clustered at one end so they appear to lean to one side.
The mean is dragged to the left or right because it is affected by extreme scores
What is a negative skew?
Where the tail is to the left (which means the values are towards the right)
What is a positive skew
Where the tail is to the right (which means the values are towards the left)
What do they both have in common?
In both instances, the mode remains at the highest point on the curve because the mode is unaffected by extreme scores