A canning machine is used to fill cans of soda To test the m

A canning machine is used to fill cans of soda. To test the machine 55 samples were taken and weighed. The mean of these samples was 15.57 OZ with a standard deviation of 0.4 OZ. Compute the upper limit to the confidence interval using an alpha value of 0.15.

Solution

Note that              
      
Upper Bound = X + z(alpha/2) * s / sqrt(n)              
              
where              
alpha/2 = (1 - confidence level)/2 =    0.075          
X = sample mean =    15.57          
z(alpha/2) = critical z for the confidence interval =    1.439531471          
s = sample standard deviation =    0.4          
n = sample size =    55          
              
Thus,              
              
Upper bound =    15.64764255   [ANSWER]