## Statistical Process Control Assignment

20 Feb

Statistical Process Control Assignment

The following sample information was obtained by taking five doughnuts per hour for twelve hours from Fawcett Bakery’s doughnut process and weighing them.

Place graphs here.
Weight (grams)
Hour    1st    2nd    3rd    4th    5th        x-bar    R
1     95    92    90    96    94
2     98    104    97    87    106
3     97    89    89    95    91
4     106    99    95    93    101
5     108    105    111    109    107
6     95    92    90    96    94
7     115    92    87    89    94
8     95    92    90    96    94
9     113    100    92    82    102
10     125    135    125    132    137
11     95    105    95    82    107
12     110    92    97    86    94

a) Find the x-bar and R for each sample    x-bar =    see above
R =     see above        Note:  You must include formulas for full credit — do NOT simply type in answers.  Add additional cells if necessary, but label each clearly!
b) Find the x-bar-bar and R-bar for the twelve samples.    X-bar-bar =            Assuming 3 standard deviations as control limits….
R-bar =                        A2 =
c) Find the 3-sigma UCL and LCL for the mean and range charts?    UCL for X-bar=
LCL for x-bar=

UCL for Range=                        D4 =
LCL for Range=                        D3 =

d) Does the process look to be in statistical control?  Why or why not?
e) Although you’re not an expert on the doughnut making process, select 3 potential causes of process variation that should be evaluated in a Lean Six-sigma project — and give a “doughnut making” example for each.    1)
2)
3)