Measures of Central Tendancies

Cards (10)

What is the mean?
The average of all the values
Evaluate using the mean
+Considers all data and exact distance between values
-High sensitivity so can be easily distorted by outliers
-Cannot be used for nominal data
What is the median?
The mid point between values in order
Evaluate the median
+Not effected by extreme scores or outliers
+Appropriate for ordinal data and easy to calculate
-Not sensitive as exact values are not reflected
What is the mode?
The most common value
Evaluate the mode
+Not effected by extreme scores or outliers
+Appropriate for nominal data
-Difficult to describe data when there is several modes
What is the range?
The distribution in scores, the bigger the range the more likely the results are effected by extraneous variables.
Evaluate the range
+Identifies how spread out the data is as it accounts for end values
-Can be effected by extreme values so may be unrepresentative
How do you calculate standard deviation
Work out the mean for the data set. Subtract the mean from each data point. Square the result. Add the values up. Divide the total by n-1 (n is number of data point). Calculate the square root.
Evaluate standard deviation
+Precise measure of dispersion as all values included
+Not effected by extreme values or outliers
-Can hide characteristics like extreme values