A visit to a hospital emergency room for something as simple

A visit to a hospital emergency room for something as simple as a sore throat could have a mean cost of $321.   Assume that this cost is normally distributed with a standard deviation of $93. If you want to be in the bottom 50%, what will be the cut-off dollar amount?

Solution

First, we get the z score from the given left tailed area. As          
          
Left tailed area =    0.5      
          
Then, using table or technology,          
          
z =    0      
          
As x = u + z * s,          
          
where          
          
u = mean =    321      
z = the critical z score =    0      
s = standard deviation =    93      
          
Then          
          
x = critical value =    321   [ANSWER]