Median is an important measure of central tendency for all of the following characteristics except
|B|| Survival Time,|
Ref: High Yield Biostatistics, pg- 11
Please remember one very important fact about the measures of central tendencies:
1. Whenever the distribution is symmetrical that is normally distributed without the presence of extreme values or outliers, mean is a good measure of central tendency.
2. The moment distribution becomes asymmetrical or skewed that is there are extreme values present in the distribution mean no longer remains a good measure of central tendency. Under such circumstances median becomes more useful as it does get affected by the outliers.
In the above questions, out of the various options it is the BP which is normally distributed in the population and hence mean would be more informative.
Measures of central tendency:
The three measures are – mean, median and mode. All three are used for numerical data, and the median and mode can be used for ordinal data as well. Mean is used for numerical data and symmetric (normal) distributions.
Arithmetic Mean- Simply an average
a. Total of all the values
b. Divide by no. of observations
c. Advantage- It is easy to calculate and understand
d. Disadvantage- Outliers, any value which is in extreme, mean gets affected
Median- Middle most value
a. Odd Nos. - Simple middle value
b. Even Nos. - Average of 2 middle values
c. Main advantage- not affected by outliers
Mode- The value that gets repeated the most
Not of much value in medical statistics