## (solution) The data excel file is attached. Construct comparative boxplots

The data excel file is attached.

1. Construct comparative boxplots for the thicknesses of new wafers and recycled wafers.
2. Identify all outliers.
3. Should any of the outliers be deleted? If so, delete them and redraw the boxplots.
4. Identify any outliers in the redrawn boxplots. Should any of these be deleted? Explain.
5. Are the distributions of thicknesses skewed, or approximately symmetric?
6. Delete outliers as appropriate, and compute the mean thickness for new and for recycled wafers.
7. Delete outliers as appropriate, and compute the median thickness for new and for recycled wafers.
8. Delete outliers as appropriate, and compute the standard deviation of the thicknesses for new and for recycled wafers.
9. Suppose that it is desired to use the type of wafer whose distribution has less spread. Write a brief paragraph that explains which type of wafer to use and why. Which measure is more useful for spread in this case, the standard deviation or the interquartile range? Explain.

New Recycled

90

91.8

91.1

92.6

96.7

92.4

92

91.7

92.2

94.5

89.8

90.3

93.7

91.7

94.6

97.4

94.9

93.9

91.5

92.8

93.9

91.6

93.7

95.1

92.7

77.3

91.5

91.6

87.9

91.1

94

96.7

91.6

92

90.6

92.7

90.4

88

89.3

77.5

88.2

89.9

93.1

91.7

92

92.4

90.1

91.4

92

87.9

88.9

89.3

90.5

88.7

91.3

90.5

98.2

92.8

92.5

95.5

95.2

92.9

92.7

95.2

96

93.3

92.4

93.6

94.3

92.6

94.5

93.1

Solution details:

STATUS

QUALITY

Approved

Sep 13, 2020

EXPERT

Tutor