Describing scale data Flashcards
What data does a histogram show?
The distribution of a scale variable using banded catergories
What is the tallest point of a histogram called??
Modal point
What can the modal point be used for?
To infer the typical of average value in the data (like the mode)
When using histograms, despite having similar mean scores, the distraction of cases for each variable can be very different (how long or wide data is), what does this variation indicate?
Variation indicates the extent to which values deviate from the typical (e.g average) value
What is standard deviation?
A quantity expressing by how much the members of a group differ from the mean value of the group
What would a low standard deviation mean?
Cases in the data tend to be clustered around the mean
What would a high standard variation mean?
Cases are dispersed over a wider range of values/ categories
What is skewness?
Skewness tells you whether cases are distributed evenly either side of the centre value
Why Will skewness inflate the size of standard deviation?
Because the long “tail” with skewness (non normally distributed data) has cases dispersed over a wider range of categories
What is a bell curve?
Normal distribution: data is equal on either sides of the centre value
What is the centre value?
If you had a line graph where the x axis is ranked 1-100, the centre value is 50
What would a positively skewed graph look like?
Most cases are towards the left with a long tail to the right
