{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

664 HW7 Solns

# 664 HW7 Solns - Statistics 664 Autumn 2010 Homework 7...

This preview shows pages 1–3. Sign up to view the full content.

Statistics 664 – Autumn 2010 Homework 7 Solutions 1. Problem 6.7 (just redo part a of 6.2) Here are the x and s charts from Minitab. 19 17 15 13 11 9 7 5 3 1 15.0 12.5 10.0 7.5 5.0 Sample Sample Mean _ _ X= 10.32 UCL= 14.73 LCL= 5.92 19 17 15 13 11 9 7 5 3 1 6.0 4.5 3.0 1.5 0.0 Sample Sample StDev _ S= 2.703 UCL= 6.125 LCL= 0 Xbar-S Chart of Ex6-2V All points are within the control limits for both charts. Thus the process appears to be in control if we assume that the historical values for x and s represent “in control” values. (Note: An acceptable alternative answer is the following. The nominal output voltage is supposed to be 350V. This means that the x i values should fluctuate around 0, i.e., that the center line in our x chart should be 0. The upper and lower control limits would then be LCL = -4.40 and UCL = 4.40. Since all the points are above 5.77, every point would be above the UCL and the process would be declared out of control). 2. Problem 6.8 (just redo part a of 6.3) Here are the x and s charts from Minitab.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
19 17 15 13 11 9 7 5 3 1 40 20 0 -20 Sample Sample Mean _ _ X= 10.9 UCL= 46.91 LCL= -25.11 19 17 15 13 11 9 7 5 3 1 60 45 30 15 0 Sample Sample StDev _ S= 25.23 UCL= 52.71 LCL= 0 Xbar-S Chart of Ex6-3Dia All points in both charts are with the control limits so the process appears to be in control, assuming the historical values represent “in control” values. (Note: An alternative answer is to argue that if the process is in control the mean should be 0. This should be the center line of the x chart. In this case, the control limits would be LCL = –36.01 and UCL = 36.01. All the data lie within these control limits, but after sample 7 all are positive, which would be considered unusual. So one might argue that the process is not in control after sample 7.) 3.
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 9

664 HW7 Solns - Statistics 664 Autumn 2010 Homework 7...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online