To find the median value, we need to arrange the values in order from least to greatest and then find the middle value.
Arranging the values:
$150,000 (2)
$220,000 (4)
$490,000 (3)
$540,000 (2)
$800,000 (5)
$975,000 (2)
The total number of houses is 18, so the middle value would be the 9th value when arranged in order.
The 9th value would fall between the $490,000 (3 houses) and $540,000 (2 houses) values. Since it's between two values, the median value would be the average of these two values:
Median = ($490,000 + $540,000) / 2
Median = $515,000
Therefore, the median value of the houses on Mango Street is $515,000.