If i=1∑9(xi−5)=9andi=1∑9(xi−5)2=45 then the standard deviation of the 9 items x1,x2,…..,x9 is
Find the standard deviation for the following data: (i) x: , 3, 8, 13, 18, 23 f: , 7, 10, 15, 10, 6 (ii) x: , 2, 3, 4, 5, 6, 7, 7 f: , 4, 9, 16, 14, 11, 6, 6
Let x1, x2,…., xn values of variable X and let ′a′ be non zero real number. Then prove that the variance of the observations ax1, ax2,…, axn is a2 Var (X) . Also, find their standard deviation.
The mean and standard deviation of 20 observations are found to be 10 and 2, respectively. One rechecking, it was found that an observation 8 was incorrect. Calculate the correct mean and standard deviation in each of the following cases. (i) If wrong item is omitted (ii) If it is replaced by 12.
The mean deviation for n observations x1,x2,………,xn from their mean X is given by (a)i=1∑n(xi−X) (b) n1i=1∑n(xi−X) (c) i=1∑n(xi−X)2 (d) n1i=1∑n(xi−X)2
In a mathematics test given to 15 students, the following marks (out of 100) are recorded:
Find the mean, median and mode of this data.
The mean and standard deviation of six observation are 8 and 4 respectively. If each observation is multiplied by 3, find the new mean and new standard deviation of the resulting observations.