Numerical measures Flashcards
What is variability?
The measure of spread
How do you work out median?
n+1/2
What is standard deviation?
A typical distance that a value is from the mean
A kind of average distance from the mean
How to compare distribution?
What do median and mean show eg increase or decrease
What do IQR and standard deviation show
What does it mean if data is unimodal?
It has one peak
What does it mean if data is negatively skewed?
The data is concentrated in the upper part of the range
What does it mean if data is bimodal?
There are two peaks
What does it mean if the data is positively skewed?
The data is concentrated in the lower part of the range
What terms can you use to describe distributions?
Symmetrical Positively skewed Negatively skewed Unimodal Bimodal
What is the equation for a histogram?
Frequency = k x area bar
(GCSE) FD=frequency/class width
If the distribution is skewed then what should you use?
The median because it isn’t distorted by outliers
