Freckles are defects that sometimes form during the solidification of alloy ingots. A freckle index has been developed to measure the level of freckling on the ingot. A team of engineers conducted several experiments to measure the freckle index of a certain type of super alloy (Journal of Metallurgy, Sept. 2004). The data for n = 18 alloy tests are shown in the table.

a. Construct a box plot for the data and use it to find any outliers.
b. Find and interpret the z-scores associated with the alloys you identified in part a.

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16.4 2.4 12.6 4.1 1.4 22.0 3.2 16.8 6.8 14.6 10.0 12.0 30.1 2.5 22.2 33.4 8.1 15.1