A quality analyst wants to construct a control chart for determining whether three machines, all producing the same product, are in control with regard to a particular quality variable. Accordingly, he sampled four units of output from each machine, with the following results. It is known from previous experience that the standard deviation of a typical machine is measured as 2.12: Machine Measurements #1 17 15 15 17 #2 16 25 18 25 #3 23 24 23 22 What are the x-bar chart three-sigma upper and lower control limits?

7 is the median   7.875 is the mean

step-by-step explanation:

3,4,5,6,8,11,13,13

yes, gavin is right.

step-by-step explanation:

gavin is correct. 

this problem is about converting 9% per year to how many percent per quarter. the rate is still the same. it only differed in the time period. so, through dimensional analysis,

9% per year  × (1 year / 4 quarters) = 2.25% per quarter

if he was asked to convert 9% per year to how many percent per quarter  compounded quarterly, then you will not simply divide by four. this is because compounding is not linear.

hope this , have a good day. c;