A random sample of 51 undergraduate statistics students resu

A random sample of 51 undergraduate statistics students resulted in a sample mean age of 23.2 years, with a sample standard deviation of 4.9 years. Find the upper bound of the 99% confidence interval for the true mean age, to one decimal place

Solution

Note that              
      
Upper Bound = X + z(alpha) * s / sqrt(n)              
              
where              
alpha = (1 - confidence level) =    0.01          
X = sample mean =    23.2          
z(alpha) = critical z for the confidence interval =    2.326347874          
s = sample standard deviation =    4.9          
n = sample size =    51          
              
Upper bound =    24.79619391   [ANSWER]