Preppy Cola, Inc. uses SPC to ensure that cans of soda meet a weight requirement
ID: 3322368 • Letter: P
Question
Preppy Cola, Inc. uses SPC to ensure that cans of soda meet a weight requirement of 12 oz. They take samples of 70 cans and reject those that weigh below 12 oz. Recent study, using 200 in control samples, shows that this process has a random process mean of p-bar = 0.09. What are the control limits and the 2 sigma warning limits for this process?
UCLp = 0.193; LCLp = -0.068; +2SigmaWLp = 0.158; -2SigmaWLp = 0.022
UCLp = 0.193; LCLp = 0.000; +2SigmaWLp = 0.158; -2SigmaWLp = 0.022
UCLp = 0.151; LCLp = 0.000; +2SigmaWLp = 0.130; -2SigmaWLp = 0.050
UCLp = 0.151; LCLp = -0.040; +2SigmaWLp = 0.130; -2SigmaWLp = 0.050
UCLp = 0.094; LCLp = 0.000; +2SigmaWLp = 0.093; -2SigmaWLp = 0.087
UCLp = 0.193; LCLp = -0.068; +2SigmaWLp = 0.158; -2SigmaWLp = 0.022
UCLp = 0.193; LCLp = 0.000; +2SigmaWLp = 0.158; -2SigmaWLp = 0.022
UCLp = 0.151; LCLp = 0.000; +2SigmaWLp = 0.130; -2SigmaWLp = 0.050
UCLp = 0.151; LCLp = -0.040; +2SigmaWLp = 0.130; -2SigmaWLp = 0.050
UCLp = 0.094; LCLp = 0.000; +2SigmaWLp = 0.093; -2SigmaWLp = 0.087
Explanation / Answer
here std error =(p*(1-p)/n)1/2 =0.0342
therefore UCLp =pbar +3*Std errror =0.193
and LCLp =pbar -3*Std errror =0.0000(cause it can not be negative)
for +2SigmaWLp =pbar +2*Std errror =0.158
for -2SigmaWLp =pbar -2*Std errror =0.0.022
hence correct option is :
UCLp = 0.193; LCLp = 0.000; +2SigmaWLp = 0.158; -2SigmaWLp = 0.022