In a marketing survey a random sample of 1072 supermarket sh

In a marketing survey, a random sample of 1072 supermarket shoppers revealed that 478 always stock up on an item when they find that item at a real bargain price.

Solution

Note that      
      
n = z(alpha/2)^2 p (1 - p) / E^2      
      
where      
      
alpha/2 =    0.025  
       
      
Using a table/technology,      
      
z(alpha/2) =    1.959963985  
      
Also,      
      
E =    0.02  
p = 478/1072 = 0.445895522  
      
Thus,      
      
n =    2372.79906  
      
Rounding up,      
      
n =    2373   [ANSWER]