Importance of central tendency It is Representative score of group 2-- Indirect description of the population 3-- Comparison of performance of two group Type of central tendency 1--MEAN 2—MEDIAN 3—MODE

Measures of central Tendency Measures of central tendency Measure of central tendency is a statistical calculation from a set of independent observation and measurement of a certain item or entry and intended totypify the observation. English &English

MEAN---The arithmetic mean, or more simply the mean,is the sum of the separate scores or measures divided by their number. Garrett Calculation of mean when data are ungrouped Formula 0f mean Where IS----- M=EX/N M=Mean X=Score E=Sum of score N=No. of score Scores M ==128/4== 32

Calculation of Mean from grouped data (long method) Formula of mean (Long Method) Where is M= Efx/N M=mean f==frequency X=Midpoint of class interval N==no offrequency CI f x fx M ean== Mean= ____ _________ N=60 Efx=6100

Median When ungrouped scores or other measures are arranged in order of size,the median is the midpoint in the series. Garrett. Median is the value that separates all the cases in a ranked distribution into halves. Warren. Median is that score in the ranked distribution which has exactly half of the cases below it and half of above it. English &English

Calculation of median when data are ungrouped N Mdn = = 4= , 10,18,22,19,21,17 = 10,16,17,18,19,21,22= 7+1/2=8/4=4 th item Median =18

Calculation of median when data are grouped CI f Cf N/2--CF Md = l x CI f / = x — x = = Median-- =101.5

MODE Gilford—In a distribution of group data, the crude mode is the mid –point of the class interval having the greatest frequency. 10,13,10,7,9,5,7,10,5,7,5,8,8,9,5,10,9, 10,9,12,13,14,13,10,11,20,15 Mode= 3XMedian –2 Mean Mo