1 The median is the middle value of the data set. 2  The lower quartile (Q 1) is the median of the lower half of the data set. 3  The upper quartile (Q 3) is the median of the upper half of the data set. 4  The interquartile range (IQR) is the spread of the middle 50% of the data values.
Removable Essix retainers typically cost between $100-$250 for one or $200-$500 for two. They are made from a vacuum sealed clear plastic that is less noticeable but more likely to break or warp, meaning that you could be paying the price more than once for this style of retainer.
In a third, hybrid model, physicians continue to see nonâretainer patients, while charging a fee to some of their patients for increased services. A typical retainer fee appears to be about $1,500 to $2,000, although the physicians we interviewed charge from $600 to $5,400.Most retainer physicians offer an inâdepth annual physical, lasting an hour or longer, which focuses on preventive care.n a third, hybrid model, physicians continue to see nonâretainer patients, while charging a fee to some of their patients for increased services. A typical retainer fee appears to be about $1,500 to $2,000, although the physicians we interviewed charge from $600 to $5,400.