The average score for 49 teenage boys playing a certain comp

The average score for 49 teenage boys playing a certain computer game was 80,000 points per player. If the standard deviation of the population is 20,000 points, find the right bound of the 95% confidence interval of the mean score for all teenage boys. For example, if the confidence interval is 100 < < 200, the right bound is 200. Round to the nearest integer

Solution

Note that              
              
      
Right Bound = X + z(alpha/2) * s / sqrt(n)              
              
where              

alpha/2 = (1 - confidence level)/2 =    0.025          
X = sample mean =    80000          
z(alpha/2) = critical z for the confidence interval =    1.959963985          
s = sample standard deviation =    20000          
n = sample size =    49          
              
Thus,              
              
Right bound =    85599.8971   [ANSWER]