If `barx_1,barx_2,barx_3,...barx_n` are the means of n groups with `n_1,n_2,n_3,....n_n` numbers of observations respectively. Than the mean `barx` of all group together is given by :

If barx_1,barx_2,barx_3,….., barx_n are the means of n groups with n_1,n_2,…..n_i numbers of observation respectively , then the mean barx of all the group taken together is given by

If barx_(1), barx_(2), barx_(3),………barx_(n) are the means of n groups with n_(1), n_(2), …………,n_(n) number of observations, respectively, then the mean barx of all the groups taken together is given by

If barx_(1), barx_(2), barx_(3),………barx_(n) are the means of n groups with n_(1), n_(2), …………,n_(n) number of observations, respectively, then the mean barx of all the groups taken together is given by

If the mean of n observations x_1,x_2,x_3...x_n is barx then the sum of deviations of observations from mean is

If barx_1 and barx_2 are the A.M. of two sets with n_1 and n_1 observation respectively, then prove that combined mean for two sets (barx) lies between barx_1 and barx_2 .

Let barx_(1)andbarx_(2) (where barx_(2)gtbarx_(1) ) be the means of two sets comprising n_(1)andn_(2) (where n_(2)ltn_(1) ) observations respectively. If barx is the mean when they are pooled, then which one of the following is correct ?

Mean of n observations x_1,x_2 ,…., x_n is barx . If an observation x_q is replaced by x'_q , then the new mean is :

The mean of the series x_1, x_2,...x_n is barX . If x_2 is replaced by lambda then the new mean is

Let x_1, x_2 ,…………,x_n be n observations and barx be their arithmetic mean. The formula for the standard deviation is given by ……….. .

Let barx be the mean of n observations x_(1),x_(2),……..,x_(n) . If (a-b) is added to each observation, then what is the mean of new set of observations?