Consider the following examples of two different types of statistical investigations. Example 1 Radio rating services sometimes collect data on listenership by asking participants to record the date, time, and station each time they listen to the radio.
Popular types of invisible braces include ceramic brackets, inside braces and clear aligners. Ceramic braces are just like metal braces, except that they use tooth-colored brackets (and sometimes tooth-colored wires) rather than metal to straighten teeth.
Traditional metal braces are the most common type of braces. These braces have a metal bracket with elastic (rubber band) ties holding the wire onto the metal brackets. The second-most common type of braces are self-ligating braces that do not require elastic ties. Instead, the wire goes through the bracket.