PAAS- week 6- describing sets of measurements Flashcards
What is a measure of central tendency?
A single value that attempts to describe a set of data by identifying the central position within that set of data.
What are the ways of describing the typical or average value known as?
Measures of central tendency
What is the mode?
What is the easiest way to find it?
The most frequent value in a set of measurements.
Draw a plot and look for the tallest bar.
What levels of measurement is the mode used for?
Nominal & categorical
It is NOT informative for continuous variables- such as height (as everyone is a unique height- so there wouldn’t be a common number)
What is the median?
Middle value- half the numbers in the data are above & half below.
To calculate a meaningful median - what must the variable be measured on?
An ordinal level.
How do you calculate the mean?
Add up all the values, then divide by the number of values in the dataset.
What are the advantages the mean compared to the median?
Mean- easier to work out mathematically.
Means taken from different samples of the same population tend to be more similar to each other.
What are the disadvantages of the mean compared to the median?
The mean is sensitive to extreme values- when the median isnt.
What is the sample mean?
The mean calculated from a group of random variables, drawn from the population.
What is the population mean?
Defined as the average of the all the elements in the population.
On average- what will sample means be equal to?
Population means.
