Statistical methods in medical research

It is a well known fact that statistics can be misleading. They are often used to prove a point and an easily be twisted in favor of that point. Statistics, graphics and database are used in medical field to approve, prove or disapprove theories, analysis and interpretation of ailments, medications and its impact and treatment and its effectiveness. As noted by Nursing Research (2011)/ “Health Information is very often explained in statistical terms for making it concise and understandable (Basic Statistical Concepts, 2011, para.

1). Statistics play a large role in research and just like anything statistical data can be misrepresented. Data can be misguiding if the sampling is not done properly.

The misrepresentation of data can occur unintentionally as a result of human error or intentionally through bias misleading. (Graphical Misrepresentation, 2006) Unintentional misrepresentation can occur through bad sampling which is usually conclusive of sampling a small group in order to represent characteristics of a larger group or population. (Basics Statistical Concepts, 2011). One thing that can easily cause misrepresentation in data is the difference between association and causation—although “variables may be affected by a knowledge of another, does not mean that one variable causes another (Armitage, Berry, & Matthews, 2008).

Question 2
What are the characteristics of a population for which it would be appropriate to use mean/median/mode? When would the characteristics of a population make them inappropriate to use? Answer:
The mean is the arithmetic average of all numbers; the sum of all values divided by the total number of values. The median is the middle value in a set of numbers arranged in order of magnitude. The mode is the value that
occurs most often. Appropriateness of each measure:

1.Arithmetic mean is used when –

In depth study of the variable is needed
The variable is continuous and additive in nature
The data are in the interval or ratio scale
When the distribution is symmetrical

2. Median is used when –

The variable is discrete
There exists abnormal values
The distribution is skewed
The extreme values are missing
The characteristics studied are qualitative
The data are on the ordinal scale

3. Mode is used when –

The variable is discrete
There exists abnormal values
The distribution is skewed
The extreme values are missing
The characteristics studied are qualitative

Inappropriateness of each measure:

1. Mean-

It is inappropriate to use the mean to summarize nominal and ordinal data. If the distribution is skewed or has some outliers, the mean will be distorted.

2. Median-

It is inappropriate to use the median to summarize nominal data.

3. Mode-

The mode may not exist.

References
Armitage, P., Berry, G, & Matthews, S. ( 2008, April). Statistical methods in medical research. John Wiley & Sons. Graphic Misrepresentation (2006)
Nursing Research (2011). Basic Statistical Concept (2011).