Cost- sampling decisons
σ x¯ =S/√n
Where is the standard error of he mean is the standard devaluation of the population and n is the sample size. Here the standard error of the mean is expressed in terms of money i, e. ± Rs. 10. If the standard deviation is 100 the factor for 95 percent confidence is 1.96 of standard deviation. Thus the actual size of the sample would be
10/ 1.96 = 100/√n
√n = 196/10
N = 384
The total cost of the budget been reduced from Rs.8000 to Rs. 7680= ( 384x 20)
Another alternative may be to increase the allowable error from a lower level to higher level provided it does not affect the attitude of the respondents. For example if the error is increased to 15, the sample size will be
σ x¯ =s/√n
1.5/1.96= 100√n
√n= 196/ 15
N= 169
Thus the total budget will be reduced from Rs. 8000 to Rs. 3380= ( 196x 20)