Most commonly used measure of central tendency-

Ans. is 'a' i.e., Mean * The commonly used statistical average (measures of central tendency) are (i) Arithmetic mean, (ii) Median and (iii) Mode.Arithmetic mean* It is the most commonly used statistical average. It is obtained by sum of all the values divided by total number of values.Mean =[?]x----e* The major disadvantage of mean is that it may be unduly influenced by abnormal high or low values in the distribution.Median* It is the middle most value in a distribution arranged in ascending or descending order. If there are two values in the middle, instead of one, the median is worked out by taking the average of two middle values.* The main advantage of median is that it is not affected by abnormal high or low values (unlike mean). Therefore, median is used in skewed distribution (distribution which is skewed/deviated due to small number of very high or low values).Mode* It is the most frequently occuring value in a distribution. If there are two most frequent values, there are two modes and the distribution is called 'bimodal distribution In bimodal distribution the mode is the average of two modes.* For bimodal distributionMode = (3 x median) - (2 x mean)* Mode is the central tendency which is least affected by extreme values or skewness (But median is the preferred central tendency in skewed distribution).