=+7.33 Ten measurements of the steam rate (in pounds per hour) of a distillation tower were used to construct the following normal probability plot (“A Self-Descaling Distillation Tower,” Chemical Engineering Process

[1968]: 79–84):

+

+

+

+

+-----+-----+-----+-----+-----+

-1.60 -0.80 0.00 0.80 1.60 2.40 Observation Normal score 900.

1200.

1500.

1800.

*

*

*

*

*

*

*

*

*

*

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