15. Graphs Flashcards
What is a scattergram ?
A type of graph that represents the strength and direction of a relationship between co variables
What is a bar chart ?
The frequency of each variable is represented by the height of the bars
What is a histogram ?
The bars touch each other which shoes that data is continuous rather than discrete
What is a line graph ?
Represents continuous data and uses points connected by lines to show how something changes in value
When would we use a bar chart ?
When data is divided into categories (discrete)
When would you use a scattergram ?
To show associations between do variables
What is normal distribution?
A symmetrical spread of frequency data that forms a bell shaped pattern. The mean, median and more are all located at the highest peak
What is meant by a skewed distribution ?
A spread of frequency data that is not symmetrical, the data clusters to one end
What is a positive skew ?
Most of the distribution is concentrated on the left, resulting in a long tail on the right
E.g. a very difficult test in which most people got low marks and a handful at the higher end
What happens to the mean, median and more in a positive skew ?
The mode remains at the highest point of the peak
The median comes next
The mean has been dragged across to the right due to the extreme scores
What is a negative skew ?
Most of the distribution is concentrated towards the right resulting in a long tail on the left
What happens to the mode, median and mean in a negatively skewed diagram ?
The mode remains at the highest peak
The median comes next
The mean has been dragged across to the right due to the extreme scores
