Stable cost reporting in a manufacturing setting is typically a sign that operations are running smoothly. The accounting department at Rockwell Collins, an avionics manufacturer, analyzes the variance of the weekly costs reported by two of its production departments. A sample of16cost reports for each of the two departments shows cost variances of2.3and5.4, respectively. Is this sample sufficient to conclude that the two production departments differ in terms of unit cost variance? Usea = 0.10(to2decimals).

What is the test statistic =________ ?