By convention, specific symbols represent certain sample statistics. For example, 1  x refers to a sample mean. 2  s refers to the standard deviation of a sample. 3  s 2 refers to the variance of a sample. 4  p refers to the proportion of sample elements that have a particular attribute.
As the name implies, lubricant laxatives make stools slippery. The mineral oil within these products adds a slick layer to the intestine's walls and stops the stool from drying out. Though highly effective, lubricant laxatives are best used as a short-term cure for constipation. Over a longer period, mineral oil can absorb fat-soluble vitamins from the intestine, and decrease certain prescription drugs from being fully absorbed into the body.
Taking mineral oil by mouth can cause nausea, vomiting and stomach cramping. Because mineral oil is taken generally at night on an empty stomach, nausea is a common side effect of oil-based laxatives.