Correct Answer - Option 4 : Harmonic Mean
Measures of central tendency provide a single value that indicates the general magnitude of the data and this single value provides information about the characteristics of the data by identifying the value at or near the central location of the data.
The three measures of central tendency are: Mean or Arithmetic mean, Median and Mode.
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Mean is a total of all the scores in data divided by the total number of scores. For example, if there are 100 students in a class and we want to find mean or average marks obtained by them in a psychology test, we will add all their marks and divide by 100, (that is the number of students) to obtain the mean. The value of the mean can be determined graphically.
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The median is the value of the middle observation when the series is arranged in order of size or magnitude. To locate the median graphically, draw less than cumulative frequency curve.
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Mode is the score in a distribution that occurs most frequently. Taking the example of the marks obtained by a group of 100 students in the psychology test discussed earlier if out of these 100 students, 10 students obtained 35 marks. 35 is thus, the most frequently occurring value and will be termed as mode. In grouped data, the value of mode can also be determined graphically.
The harmonic mean is a measure of central tendency for data expressed as rates such as kilometers per hour, tonnes per day, kilometers per liter, etc.
- The harmonic mean is useful for computing the average rate of increase of profits, or average speed at which a journey has been performed, or the average price at which an article has been sold. Otherwise, its field of application is really restricted.
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The harmonic mean as the arithmetic mean and geometric mean is computed from each and every observation. It is especially useful for averaging rates but it cannot be determined graphically.
Thus, it is clear that A statistical measure that cannot be determined graphically is the Harmonic mean.
