Q.

If every term of the statistical data consisting of terms is decreased by 2, then the mean of the data:

1 decreases by 2
   
2 remains unchanged  
3 decreases by 2n  
4 decreases by 1  

Ans.

(1)

Let n terms of data be

x1,x2,x3,,xn.  Mean (x¯)=i=1nxinNow, when each term is decreased by 2.Data will be x1-2,x2-2,x3-2,,xn-2New mean==i=1n(xi-2)n=i=1nxin-2nn=x¯-2" Mean is also decreased by 2."