Freckling of superalloy ingots. 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 superalloy (Journal of Metallurgy, Sept.

2004). The data for n = 18 alloy tests are shown in the table.

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

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.