Bias is the term used in statistics to describe a systematic distortion in the samples obtained for the parameter being estimated. It is evident by obtaining values higher or lower than that of the average population for the parameter being measured. As such the data is a misrepresentation of the population and cannot be trusted to give a good indices of things.
This sample has a bias because the concerned citizen opted to use a <em>convenience sampling</em> instead of using <em>random sampling</em>. In <em>random sampling</em>, every individual has an equal chance of being chosen which is unlike the <em>convenience sampling</em> when only a specific group of individuals can be chosen. In this case, the bias was introduced when the citizen went to stand outside the courthouse with his petition, the citizen should have taken samples across diverse geographical locations and professional institutions. The implication of this sampling is that a significant percentage of the population has been sidelined (considering they would not be in or around the courthouse) from the sampling and the sampling has been restricted to only those who have business around the courthouse. The result is that whatever samples he/she obtains will not be an accurate representation of the parameter being measure from the population.
When converting 10cm to mm you get 100mm and when putting 100mm to 103mm its visible that the 103mm is larger, but by how much? The difference is 0.3cm and/or 3mm.
