Biology Forums - Study Force

An automatic filling machine is used to fill 1-liter bottles of cola. The machine’s output is approximately normal with a mean of 0.94 liter and a standard deviation of 0.04 liter. Output is monitored using means of samples of 28 observations.

a. Determine upper and lower control limits that will include roughly 97 percent of the sample means when the process is in control. (Do not round intermediate calculations. Round z value to 2 decimal places. Round your answers to 4 decimal places.)

Are my answers correct?
Upper control limits:  .9564 liter 
 Lower control limits: .9236 liter

b. Given these sample means: 1.005, 1.001, .998, 1.002, .995, and .999, is the process in control? Yes or No? Can you explain why the answer is yes or no?

Hey again, welcome

Answer is attached!

So my answer for part a. is correct then? And I'm going to assume that part b. is No, because if part a. is correct then all of the sample means from part b. fall above the UCL.

Hi, sorry for the late reply -- slightly busy today.

I obtained this answer from the textbook's solutions manual, so I'm assuming it is entirely correct. I'm not familiar with the math, honestly, but I was hoping you or someone else would make sense of it.

Hope it helps

Thanks that cleared things up for a few parts, though it didn't show anything past part D.

There's a part D?

Sorry, the order of my questions on my screen is a little weird. My response about missing parts was supposed to be for another question, but I'm no longer in that section, so no need to figure out which one it was. (: