A recent survey by the U.S. Census Bureau determined that the median monthly housing rent was $643. If the first quartile for monthly housing rent was $479, find the percent of monthly housing rents that were the following values:
a. more than $570.
b. less than $708.
c. between $570 and $708.

Using the percentile concept, it is found that:

a) 50% of monthly housing rents were more than $570.

b) 75% of monthly housing rents were less than $708.

c) 25% of monthly housing rents were between $570 and $708.

When a measure is in the xth percentile of a data-set, it is greater than x% of the measures and lesser than (100 - x)%.

The correct values are:

Item a:

The median is the 50th percentile, hence 100 - 50 = 50% of monthly housing rents were more than $570.

Item b:

The third quartile is the 75th percentile, as , hence, 75% of monthly housing rents were less than $708.

Item c:

75% - 50% = 25%, hence, 25% of monthly housing rents were between $570 and $708.

A similar problem is given at link

The interquartile range (IQR) is a measure of variability, based on dividing a data set into quartiles. Quartiles divide a rank-ordered data set into four equal parts. The values that divide each part are called the first, second, and third quartiles;