Question

a packaging company strives to maintain a constant temperature for its packages that require a specific temperature range. it is believed that the temperature of packages follows a normal distribution with a mean of 5 degrees celsius and a standard deviation of 0.3 degree celsius. inspectors take weekly samples for 5 weeks of eight randomly selected boxes and report their temperatures. the five weekly sample means are shown in the table below. week 1 4.97 week 2 5.16 week 3 5.12 week 4 5.35 week 5 5.50 how many points are outside the control limits?

Answer 1

There are no points outside the control limits, since all of the weekly sample means are within the range of 4.7 to 5.3 degrees Celsius (the mean of 5 degrees Celsius plus or minus 0.3 degrees Celsius).