Question 23

Created on Thu, 07/13/2017 - 05:17
Last updated on Thu, 07/13/2017 - 05:17
Pass rate: 8%
Highest mark:

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How can the ‘central tendency’ of data be measured (50% of marks)? How is the ‘degree of dispersion’ is described (50% of marks)?

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College Answer

There was a lack of sufficient knowledge to pass this question. The first question required a 
definition of mean, median and mode and some explanation about when the use of one 
would be preferred over another. One candidate gave an example of a simple data set (a set 
of numbers) and calculated the mean, median & mode and explained the effect of an outlier. 
This simple exercise demonstrated they had a very good understanding of the terms. 
The degree of dispersion was poorly answered. A list of measures with a sentence or 
equation describing each would have scored well. The list could have included range, interquartile range (and box and whisper plots), mean absolute deviation, variance and standard 
deviation and coefficient of variation. Not all measures needed to be discussed to pass the 
question. 
Many candidates confused standard deviation and standard error of the mean and many 
candidates failed to discuss ranges which are the simplest way to describe dispersion.