It is thought that the front cover and the nature of the fir
     It is thought that the front cover and the nature of the first question on mail surveys influence the response rate. An article tested this theory by experimenting with different cover designs. One cover was plain; the other used a picture of a skydiver. The researchers speculated that the return rate would be lower for the plain cover.  Does this data support the researchers\' hypothesis? Test the relevant hypotheses using Alpha = 0.10 by first calculating a P-value.  Compute the test statistic value and find the P-value 
  
  Solution
z = -0.20
Since it is a left-tailed test, hence
 P_value = P(Z< -0.20 )
 = 1 - P(Z< 0.20 )
 = 1 - 0.5793
 = 0.4207

