Question 1071663
mean  = 68.22 inches , variance  = 10.8 inches
Standard deviation ={{{sqrt(variance)}}}
                      ={{{ sqrt(10.8)}}}
                =3.2863
1 feet =12 inches
6 feet  = 12*6 = 72 inches
 Z score for 72 inches  =  {{{ (x-mean)/standard deviation}}}
 
                          ={{{ (72-68.22)/3.2863 }}}
                          = 1.15029
 From probability -z score chart, cumulative area for z  = 1.15029 is 0.87493 = 87.493 %
but , we need area for z > 1.15029 ( since we need no of people 6 feet or taller)
probability  =  100- 87.493 = 12.507 %
Hence probability  =  12.507 %
for 100 varieties, 12.507 varieties would be 6 feet tall