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_i numbers of observation respectively , then the mean barx of all the group taken together is given by

If bar(x)_(1),bar(x)_(2),bar(x)_(3),...bar(x)_(n) are the means of n groups with n_(1),n_(2),n_(3),....n_(n) numbers of observations respectively.Than the mean bar(x) 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_3,....n_n numbers of observations respectively. Than the mean barx of all group together is given by :

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 ?

If x_(1),x_(2)……..x_(n) be n observation and barx be their arithmetic mean .Then formula of the standard deviation is given by

If x_(1),x_(2)……..x_(n) be n observation and barx be their arithmetic mean .Then formula of the standard deviation is given by

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 x_(1),x_(2),……,x_(n) be n observations and barx be their arithmetic mean. The formula for the standard deviation 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 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?