Oxide layers on semiconductor wafers are etched in a mixture

Oxide layers on semiconductor wafers are etched in a mixture of gases to achieve the proper thickness. The variability in the thickness of these oxide layers is a critical characteristic of the wafer, and low variability is desirable for subsequent processing steps. Two different mixtures of gases are being studied to determine whether one is superior in reducing the variability of the oxide thickness. Sixteen wafers are etched in each gas. The sample standard deviations of oxide thickness are s1 = 1.96 angstroms and s2 = 2.13 angstroms, respectively. The analyst would like to make inference using this samples to determine which gas is preferable. What sampling distribution should the analyst use? A. Z distribution B. t distribution C. chi-square distribution D. F distribution

Solution

As we are comparing two sample standard deviations, then we have to use

OPTION D: F DISTRIBUTION. [ANSWER]