Test of Equality of Variances When testing two independent samples (for differences in mean, one-sided tests, etc.), it is helpful to know that the samples have equal variances or not.
JHK2303/iStock/Getty Images. Chambray, a double-ply cotton fabric with a tight weave, is similar to denim but not the same. It has a white filler thread woven in with a colored background thread. But unlike denim's twill weave, chambray has a plain weave, so it's smoother and lighter in weight.Chambray is rugged but light, making it suitable for work wear as well as summer-weight shirts and skirts.ut unlike denim's twill weave, chambray has a plain weave, so it's smoother and lighter in weight. Chambray is rugged but light, making it suitable for work wear as well as summer-weight shirts and skirts.
Challis, sometimes referred to as challie[1] or chally,[2] is a lightweight woven fabric, originally a silk-and-wool blend, which can also be made from a single fibre, such as cotton, silk or wool,[3] or from man-made fabrics such as rayon.[4] It was first manufactured in Norwich, England, in about 1832, when it was designed as a thin, soft material ...