Descriptive Statistics Flashcards
What are the measures of central tendency?
- Mean
- Median
- Mode
What is the mean?
The average that is shown by all scors in the data set when they are divided by n
What are the advantages/disadvantages of using a mean?
+Necessary for further statistical analysis e.g., standard deviation
+Can always by found when using ordinal or above data
-Influenced by anomalous results
-May produce ‘nonsense’ value not in the original data
What is the median?
The mid point in a set of data that has been placed in order
What are the advantages/disadvantages of using a median?
+Not influenced by anomalous results
+Can always be found when using ordinal or above level data
-Not useful in further statistical analysis
-May produce ‘nonsense’ value that is not in the original data set
What is the mode?
The most common value within a set of data
What are the advantages/disadvantages of using a mode?
+Can be used for data measured on a nominal scale and that is not a ‘nonsense’ value
+Value has definetly occured in the data set
-May be more than one, or no result if data is varied
-May not display what is occurring in the centre of the data set if there is a skewed disribution
What are the measures of dispersion?
- Range
- Standard deviation
What is the range?
A value that shows the spread of data, representing the difference between the lowest and highest scores
What are the advantages/disadvantages of using a range?
+Relatively easy to calculate
+Gives an indication about consistency/reliability of the data
-Is influenced by anomalous results; this is a problem because only the highest and lowest scores are considered in the calculation
What is the standard deviation?
A value that represents the amount of variation of results from the mean score
What are the advantages/disadvantages of using a standard deviation?
+More sophisticated measure of dispersion as every score is reflected in the data set
+Gives an indication of how close the majority of the scores are to the mean in a normal distribution
-Time consuming to calculate compared to the mean or range
-Not all scores will be within one standard deviation, so it can be misleading when it comes to anomalies
