Descriptive Statistics

Question 1

What are the measures of central tendency?

Answer 1

• Mean
• Median
• Mode

Question 2

What is the mean?

Answer 2

The average that is shown by all scors in the data set when they are divided by n

Question 3

What are the advantages/disadvantages of using a mean?

Answer 3

+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

Question 4

What is the median?

Answer 4

The mid point in a set of data that has been placed in order

Question 5

What are the advantages/disadvantages of using a median?

Answer 5

+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

Question 6

What is the mode?

Answer 6

The most common value within a set of data

Question 7

What are the advantages/disadvantages of using a mode?

Answer 7

+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

Question 8

What are the measures of dispersion?

Answer 8

• Range
• Standard deviation

Question 9

What is the range?

Answer 9

A value that shows the spread of data, representing the difference between the lowest and highest scores

Question 10

What are the advantages/disadvantages of using a range?

Answer 10

+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

Question 11

What is the standard deviation?

Answer 11

A value that represents the amount of variation of results from the mean score

Question 12

What are the advantages/disadvantages of using a standard deviation?

Answer 12

+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